Frederick, the son of Frederick william I and his wife, Sophia Dorothea of Hanover, was born in Berlin on 24 January 1712. He was baptised with only one name, Friedrich, and was not given any other names. The birth of Frederick was welcomed by his grandfather, Frederick I, with more than usual pleasure, as his two previous grandsons had both died in infancy. With the death of his father in 1713, Frederick william became King in Prussia, thus making young Frederick the crown Prince. The new king wished for his sons and daughters to be educated not as royalty, but as simple folk. He had been educated by a Frenchwoman, Madame de Montbail, who later became Madame de Rocoulle, and he wished that she educate his children.

As a great patron of the arts, Frederick was a collector of paintings and ancient sculptures; his favorite Artist was Jean-Antoine Watteau. The picture gallery at Sanssouci "represents a unique synthesis of the arts in which architecture, painting, sculpture and the decorative arts enter into dialogue with each other, forming a compendium of the arts." The gilded stucco decorations of the ceilings were created by Johann Michael Merck (1714–1784) and Carl Joseph Sartori (1709–1770). Both the wall paneling of the galleries and the Diamond shapes of the floor consist of white and yellow marble. Paintings by different schools were displayed strictly separately: 17th century Flemish and Dutch paintings filled the western wing and the gallery's central building, Italian paintings from the High Renaissance and Baroque were exhibited in the eastern wing. Sculptures were arranged symmetrically or in rows in relation to the architecture.

When he was 18, Frederick plotted to flee to England with Katte and other junior army officers. While the royal retinue was near Mannheim in the Electorate of the Palatinate, Robert Keith, Peter Keith's brother, had an attack of conscience when the conspirators were preparing to escape and begged Frederick william for forgiveness on 5 August 1730; Frederick and Katte were subsequently arrested and imprisoned in Küstrin. Because they were army officers who had tried to flee Prussia for Great Britain, Frederick william leveled an accusation of treason against the pair. The king briefly threatened the crown Prince with the death penalty, then considered forcing Frederick to renounce the succession in favour of his brother, Augustus william, although either option would have been difficult to justify to the Imperial Diet of the Holy Roman Empire. The king forced Frederick to watch the decapitation of his confidant Katte at Küstrin on 6 November, leaving the crown Prince to faint right before the fatal blow was struck.

Frederick was granted a royal pardon and released from his cell on 18 November, although he remained stripped of his military rank. Instead of returning to Berlin, however, he was forced to remain in Küstrin and began rigorous schooling in statecraft and administration for the War and Estates Departments on 20 November. Tensions eased slightly when Frederick william visited Küstrin a year later, and Frederick was allowed to visit Berlin on the occasion of his sister Wilhelmine's marriage to Margrave Frederick of Bayreuth on 20 November 1731. The crown Prince returned to Berlin after finally being released from his tutelage at Küstrin on 26 February 1732.

In 1732, Queen Sophia Dorothea attempted to arrange a dual marriage of Frederick and his sister Wilhelmine with Amelia and Frederick, the children of her brother, King George II of Great Britain. Fearing an alliance between Prussia and Great Britain, Field Marshal von Seckendorff, the Austrian ambassador in Berlin, bribed the Prussian Minister of War, Field Marshal von Grumbkow, and the Prussian ambassador in London, Benjamin Reichenbach. The pair slandered the British and Prussian courts in the eyes of the two kings. Angered by the idea of the effete Frederick's being so honored by Britain, Frederick william presented impossible demands to the British, such as Prussia's acquiring Jülich and Berg, which led to the collapse of the marriage proposal.

Recent major biographers of Frederick, including Alings, Blanning, Burgdorf and Hahn, are unequivocal that he was predominantly homosexual, and that his sexuality was central to his life and character. Frederick's physician Johann Georg Ritter von Zimmermann claimed that the king had suffered a minor deformity during an operation to cure gonorrhea in 1733, and convinced himself that he was impotent, but pretended to be homosexual in order to appear that he was still virile and capable of intercourse, albeit with men. This story is doubted by Wolfgang Burgdorf, who is of the opinion that "Frederick had a physical disgust of women" and therefore "was unable to sleep with them". After one particular defeat on the battlefield Frederick bluntly wrote: "Fortune has it in for me; she is a woman, and I am not that way inclined."

Frederick had despised Polish people since his youth, and numerous statements are known in which he expressed anti-Polish prejudice, calling Polish society "stupid" and stating that "all these people with Surnames ending with -ski, deserve only contempt". He passionately hated everything associated with Poland, while justifying his hatred and territorial expansion with ideas of the Enlightenment. He described Poles as "slovenly Polish trash"; referring to them in a letter from 1735 as "dirty" and "vile apes", and compared the Polish peasants to American Indians.

Frederick also aspired to be a Platonic Philosopher king like the Roman Emperor Marcus Aurelius. The king joined the Freemasons in 1738 and stood close to the French Enlightenment, corresponding with some of its key figures, such as Voltaire. The personal friendship of Frederick and Voltaire came to an unpleasant end after Voltaire's visit to Berlin and Potsdam in 1750–1753, although they reconciled from afar in later years.

The works of Niccolò Machiavelli, such as The Prince, were considered a guideline for the behavior of a king in Frederick's age. In 1739, Frederick finished his Anti-Machiavel, an idealistic refutation of Machiavelli. It was written in French and published anonymously in 1740, but Voltaire distributed it in Amsterdam to great popularity. Frederick's years dedicated to the arts instead of politics ended upon the 1740 death of Frederick william and his inheritance of the Kingdom of Prussia. Frederick and his father were more or less reconciled at the latter's death, and Frederick later admitted, despite their constant conflict, that Frederick william had been an effective ruler: "What a terrible man he was. But he was just, intelligent, and skilled in the management of affairs... it was through his efforts, through his tireless labor, that I have been able to accomplish everything that I have done since."

At age 16, Frederick seems to have embarked upon a youthful affair with a 13-year-old page of his father, Peter Karl Christoph Keith. In her biography of the king, Margaret Goldsmith says rumors of the liaison spread in the court and the "intimacy" between the two boys provoked the condemnation of even his elder and favorite sister, Wilhelmine, who was his protector in all things. Rumors finally reached King Frederick william, who cultivated in his court an ideal of ultramasculine, military life, and who enjoyed bullying his son. As a result, Keith was dismissed from his Service to the King and sent away to a regiment by the Dutch border, while Frederick was sent to Wusterhausen in order to "repent of his sin". Frederick's relationship with Hans Hermann von Katte was also believed by King Frederick william to be romantic, a suspicion which apparently enraged him. After Katte's execution by Frederick's father, Frederick was forced to marry Elisabeth Christine of Brunswick-Bevern, with whom he had no children. He immediately separated from his wife when Frederick william I died in 1740. In later years, Frederick would pay his wife formal visits only once a year. These were on her birthday and were some of the rare occasions when Frederick did not wear military uniform. In 1739 Frederick met the Venetian Philosopher Francesco Algarotti. Both were infatuated. Frederick was to make him a count. Challenged by Algarotti that northern Europeans lacked passion, Frederick penned for him an erotic poem which imagined Algarotti in the throes of sexual congress (with a female partner referred to as Chloris).

Despite his distaste for German, Frederick did sponsor the "Königliche Deutsche Gesellschaft" (Royal German Society), founded in Königsberg in 1741, the aim of which was to promote and develop the German language. He allowed the association to be titled "royal" and have its seat at the Königsberg Castle. However, he does not seem to have taken much interest in the work of the society. Frederick also promoted the use of German instead of Latin in the field of law, though mainly for practical reasons. Moreover, it was under his reign that Berlin became an important center of German enlightenment.

In early September 1741, the French entered the war against Austria and together with their allies, the Electorate of Bavaria, marched on Prague. With Prague under threat, the Austrians pulled their army out of Silesia to defend Bohemia. When Frederick pursued them into Bohemia and blocked their path to Prague, the Austrians attacked him on 17 May 1742. However, Frederick's re-trained cavalry proved to be a powerful force and ultimately Prussia claimed victory at the Battle of Chotusitz,. After this dramatic victory, and with the Franco-Bavarian forces having captured Prague, Frederick forced the Austrians to seek peace. The terms of the Treaty of Breslau between the Austrians and the Prussians, negotiated in June 1742, gave Prussia all of Silesia and Glatz County, with the Austrians retaining only that portion of Upper Silesia called "Austrian or Czech Silesia." Prussian possession of Silesia gave the kingdom control over the navigable Oder River as well as nearly doubling its population and territory. In 1744, Frederick also gained the minor territory of East Frisia (located on the North Sea coast of Germany) after its last ruler died without issue.

By 1743, the Austrians had subdued Bavaria and driven the French out of Bohemia. Frederick strongly suspected Maria Theresa would resume war with Prussia in an attempt to recover Silesia. Accordingly, he renewed his alliance with the French and preemptively invaded Bohemia in August 1744, beginning the Second Silesian War. By late August 1744, all of Frederick's columns had crossed the Bohemian frontier. Frederick marched straight for Prague and laid siege to the city. On 11 September 1744, the Prussians began a three-day artillery bombardment of Prague, which fell a few days later. Three days after the fall of Prague, Frederick's troops were again on the march into the heart of central Bohemia. However, the Austrians refused to directly engage in battle with Frederick and simply harassed his supply lines, eventually forcing him to withdraw to Silesia as winter approached. With the death of Holy Roman Emperor Charles VII of Bavaria in January 1745, Maria Theresa's husband Francis of Lorraine was elected Emperor and Saxony joined the Austrians' side against Frederick.

Frederick the Great's most notable and decisive military victories on the battlefield were the Battles of Hohenfriedberg, fought during the War of Austrian Succession in June 1745; the Battle of Rossbach, where Frederick defeated a combined Franco-Austrian army of 41,000 with a mere 21,000 Soldiers (10,000 dead for the Franco-Austrian side with only 550 casualties for Prussia); and the Battle of Leuthen, which was a follow up victory to Rossbach pitting Frederick's 36,000 troops against Charles of Lorraine's Austrian force of 80,000—Frederick's masterful strategy and tactics at Leuthen inflicted 7,000 casualties upon the Austrians and yielded 20,000 prisoners.

Frederick was a patron of music as well as a gifted musician who played the transverse flute. He composed more than 100 sonatas for the flute as well as four symphonies. The Hohenfriedberger Marsch, a military march, was supposedly written by Frederick to commemorate his victory in the Battle of Hohenfriedberg during the Second Silesian War. His court Musicians included C. P. E. Bach, Johann Joachim Quantz, Carl Heinrich Graun and Franz Benda. A meeting with Johann Sebastian Bach in 1747 in Potsdam led to Bach's writing The Musical Offering.

In the 1750s Voltaire began writing his Mémoires. The manuscript was stolen and a pirate copy was published in Amsterdam in 1784 as The Private Life of the King of Prussia. In it, Voltaire explicitly detailed Frederick's homosexuality and the circle surrounding him. The revelations and language were strikingly similar to those detailed in a scurrilous pamphlet published in French, in London in 1752. After a temporary cooling of Frederick and Voltaire's friendship, they resumed their correspondence, and aired mutual recriminations, to end as friends once more. A further intimate friendship was with his first valet Michael Gabriel Fredersdorf who, Frederick confided to his diary, had "a very pretty face": Fredersdorf was provided with an estate, and acted as unofficial prime minister.

The king founded the first veterinary school in Germany. Unusual for his time and aristocratic background, he criticized hunting as cruel, rough and uneducated. When someone once asked Frederick why he didn't wear spurs when riding his horse, he replied, "Try sticking a fork into your naked stomach, and you will soon see why." He loved dogs and his horse and wanted to be buried with his greyhounds. In 1752 he wrote to his sister Wilhelmine that people indifferent to loyal animals would not be more grateful to other humans and that it was better to be too sensitive than too harsh. He was also close to nature and issued decrees to protect plants.

Habsburg Austria and Bourbon France, traditional enemies, allied together in the Diplomatic Revolution of 1756 following the collapse of the Anglo-Austrian Alliance. Frederick swiftly made an alliance with Great Britain at the Convention of Westminster. When the neighboring countries began conspiring against him, Frederick was determined to strike first. On 29 August 1756 his well-prepared army crossed the frontier and preemptively invaded Saxony, thus beginning the Third Silesian War and the larger Seven Years' War, both of which lasted until 1763. He faced widespread criticism for his attack on neutral Saxony and for his forcible incorporation of the Saxon forces into the Prussian army following the Siege of Pirna in October 1756. While the Prussian invasion of Saxony was successful, it took uncharacteristically long to complete, costing Prussia the initiative. Frederick's subsequent 1757 invasion of Austrian Bohemia, though initially successful, ended in his first defeat at the Battle of Kolin and forced him into retreat. However, when the French and the Austrians attempted to counter-attack into Saxony and Silesia, Frederick decisively defeated them at the battles of Rossbach and Leuthen. Frederick hoped these two great victories would force Austria to negotiate, but Maria Theresa was determined not to make peace until she had recovered Silesia, and so the war continued. Despite its excellent performance, the Prussian army became increasingly stretched thin by various costly battles.

Frederick found an ally in his sister, Wilhelmine, with whom he remained close for life; he was later devastated by her death in 1758. At age 16, Frederick formed an attachment to the king's 13-year-old Scottish page, Peter Karl Christoph von Keith (de). Wilhelmine recorded that the two "soon became inseparable. Keith was intelligent, but without education. He served my brother from feelings of real devotion, and kept him informed of all the king's actions." Margaret Goldsmith, a biographer of Frederick's, suggests the attachment was of a sexual nature, and as a result thereof, Keith was sent away to an unpopular regiment near the Dutch frontier, while Frederick was temporarily sent to his father's hunting lodge at Königs Wusterhausen in order "to repent of his sin". Around the same time, he became close friends with Hans Hermann von Katte, a young Prussian officer who served as one of his tutors.

According to Scott, Frederick was eager to exploit Poland economically as part of his wider aim of increasing Prussia's wealth. Scott views this as a continuation of his previous violations of Polish territory in 1759 and 1761 and raids within Greater Poland until 1765. After acquiring dies from which the currency of Poland was struck Prussia issued debased Polish coins, which drove money out of Poland into Hohenzollern territory – this resulted in 25 million thalers in profit, while causing considerable monetary problems for Poland.

Frederick gave his state a modern bureaucracy whose mainstay until 1760 was the able War and Finance Minister Adam Ludwig von Blumenthal, succeeded in 1764 by his nephew Joachim who ran the ministry to the end of the reign and beyond. Prussia's education system was seen as one of the best in Europe. He modernized the Prussian bureaucracy and civil Service and promoted religious tolerance throughout his realm. He reformed the judicial system, allowed freedom of speech, the press and literature, and abolished most uses of judicial torture, except the flogging of Soldiers, as punishment for desertion. The death penalty could be carried out only with a warrant signed by the King himself; Frederick only signed a handful of these warrants per year, and then only for murder. He made it possible for men not of noble stock to become judges and senior bureaucrats. Langer finds that, "Prussian justice became the most prompt and efficient in Europe."

The sudden death of Empress Elizabeth of Russia in January 1762 led to the succession of her Germanized nephew (Duke of Holstein-Gottorp), pro-Prussian Peter III. This "Miracle of the House of Brandenburg" led to the collapse of the anti-Prussian coalition; Peter immediately ended the Russian occupation of East Prussia and Pomerania, returning them to Frederick. One of Peter III's first diplomatic endeavors was to seek a Prussian title from Frederick, which Frederick naturally obliged. Peter III was so enamored of Frederick that he not only offered him the full use of a Russian corps for the remainder of the war, he also wrote to Frederick that he would rather have been a general in the Prussian army than Tsar of Russia. More significantly, Russia's about-face from once an enemy of Prussia to its patron rattled the leadership of Sweden, who, seeing the writing on the wall, hastily made peace with Frederick as well. With the threat to his eastern borders over, and France also seeking peace after its defeats by Britain, Frederick was able to fight the Austrians to a stalemate, and finally brought them to the peace table. While the ensuing Treaty of Hubertusburg simply returned the European borders to what they had been before the Seven Years' War, Frederick's ability to retain Silesia in spite of the odds earned Prussia admiration throughout the German-speaking territories. A year following the Treaty of Hubertusberg, Catherine the Great (Peter III's widow and possible usurper) signed an eight-year alliance with Prussia.

During the reign of Frederick, the effects of the Seven Years' War and the gaining of Silesia greatly changed the economy. The circulation of depreciated money kept prices high. To revalue the Thaler, the Mint Edict of May 1763 was proposed. This stabilized the rates of depreciated coins that would not be accepted and provided for the payments of taxes in currency of prewar value. This was replaced in northern Germany by the Reichsthaler, worth one-fourth of a Conventionsthaler. Prussia used a Thaler containing one-fourteenth of a Cologne mark of silver. Many other rulers soon followed the steps of Frederick in reforming their own currencies — this resulted in a shortage of ready money, thus lowering prices.

Frederick became concerned, however, after Russia gained significant influence over Poland in the Repnin Sejm of 1767, a position which also threatened Austria and the Ottoman Turks. In the ensuing Russo-Turkish War (1768–74), Frederick supported Catherine with a subsidy of 300,000 rubles, albeit with reluctance as he did not want Russia to become even stronger through acquisitions of Ottoman territory. The Prussian king achieved a rapprochement with Emperor Joseph and the Austrian chancellor Kaunitz.

After Russia occupied the Danubian Principalities in 1769–70, Frederick's representative in Saint Petersburg, his brother Prince Henry, convinced Frederick and Maria Theresa that the balance of power would be maintained by a tripartite division of the Polish–Lithuanian Commonwealth instead of Russia taking land from the Ottomans. They agreed to the First Partition of Poland in 1772, which took place without a war. Frederick claimed most of the Polish province of Royal Prussia. Prussia annexed 20,000 square miles (52,000 km) and 600,000 inhabitants, the least of the partitioning powers. However, Prussia's Polish territory was also the best-developed economically. The newly created province of West Prussia connected East Prussia and Farther Pomerania and granted Prussia control of the mouth of the Vistula River. Frederick also invited German immigrants to the province, hoping they would displace the Poles. Maria Theresa had only reluctantly agreed to the partition, to which Frederick sarcastically commented, "she cries, but she takes".

In one defining respect Frederick would come to the throne with an exceptional inheritance. A Prussian population estimated at 2.24 million might not be enough to confer great power status, but it turned out that an army of 80,000 men could be. The ratio of one soldier for every 28 citizens can be compared with a ratio of one soldier for every 310 citizens in Great Britain, frequently an indispensable ally and another aggressively expansionist power during the middle part of the eighteenth century. Moreover, the Prussian infantry trained by Frederick william I were, at the time of Frederick's accession, arguably without rival in discipline and firepower. By 1770, after two decades of punishing war alternating with intervals of peace, Frederick would have doubled the size of the huge army that he had inherited from his father, and which during his reign would consume 86% of the state budget. The situation is summed up in a widely translated and quoted aphorism attributed to Mirabeau who asserted in 1786 that Prussia under Frederick was not a state in possession of an army, but an army in possession of a state ("La Prusse n’est pas un pays qui a une armée, c’est une armée qui a un pays.").

Frederick began titling himself "King of Prussia" after the acquisition of Royal Prussia (West Prussia) in 1772; the phrasing "King in Prussia" had been used prior to this, beginning with the coronation of Frederick I in Königsberg in 1701.

Frederick also sent in Jesuits to open schools, and befriended Ignacy Krasicki, whom he asked to consecrate St. Hedwig's Cathedral in 1773. He also advised his successors to learn Polish, a policy followed by the Hohenzollern dynasty until Frederick III decided not to let the Future william II learn the language.

Late in his life Frederick involved Prussia in the low-scale War of the Bavarian Succession in 1778, in which he stifled Austrian attempts to exchange the Austrian Netherlands for Bavaria. For their part, the Austrians tried to pressure the French to participate in the War of Bavarian Succession since there were guarantees under consideration related to the Peace of Westphalia, clauses which linked the Bourbon dynasty of France and the Habsburg-Lorraine dynasty of Austria. Unfortunately for the Austrian Emperor Joseph II, the French were unable to provide sufficient manpower and resources to the endeavor since they were already struggling on the North American continent against the British, aiding the American cause for independence in the process. Frederick ended up as a beneficiary of the French and British struggle across the Atlantic, as Austria was left more or less isolated.

In 1781 Frederick decided to make coffee a royal monopoly and disabled Soldiers were employed to spy on citizens sniffing in search of illegally roasted coffee, much to the annoyance of general population

Moreover, Saxony and Russia, both of which had been Austria's allies in the Seven Years' War, were now allied with Prussia. Although Frederick was weary of war in his old age, he was determined not to allow the Austrians dominance in German affairs. Frederick and Prince Henry marched the Prussian army into Bohemia to confront Joseph's army, but the two forces ultimately descended into a stalemate, largely living off the land and skirmishing rather than actively attacking each other. Frederick's longtime rival Maria Theresa (Joseph's mother and co-ruler) did not want a new war with Prussia, and secretly sent messengers to Frederick to discuss peace negotiations. Finally, Catherine II of Russia threatened to enter the war on Frederick's side if peace was not negotiated, and Joseph reluctantly dropped his claim to Bavaria. When Joseph tried the scheme again in 1784, Frederick created the Fürstenbund, allowing himself to be seen as a defender of German liberties, in contrast to his earlier role of attacking the imperial Habsburgs. In the process of checking Joseph II's attempts to acquire Bavaria, Frederick enlisted two very important players, the Electors of Hanover and Saxony along with several other second rate German princes. Perhaps even more significant, Frederick benefited from the defection of the senior prelate of the German Church (Archbishop of Mainz) who was also the arch-chancellor of the Holy Roman Empire, which further strengthened Frederick and Prussia's standing amid the German states.

In 1785, Frederick signed a Treaty of Amity and Commerce with the United States of America, recognizing the independence of the new nation. The agreement included a novel clause, whereby the two Leaders of the executive branches of either country guaranteed a special and humane detention for prisoners of war.

On the morning of 17 August 1786, Frederick died in an armchair in his study at Sanssouci, aged 74. He left instructions that he should be buried next to his greyhounds on the vineyard terrace, on the side of the corps de logis of Sanssouci. His nephew and successor Frederick william II instead ordered the body to be entombed next to his father in the Potsdam Garrison Church. Near the end of World War II, Hitler ordered Frederick's coffin, along with those of his father Frederick william I, World War I Field Marshal Paul von Hindenburg, and Hindenburg's wife Gertrud, to be hidden in a salt mine as protection from destruction. The United States Army relocated the remains to Marburg in 1946; in 1953, the coffins of Frederick and his father were moved to Burg Hohenzollern.

Frederick retained Jesuits as teachers in Silesia, Warmia, and the Netze District after their suppression by Pope Clement XIV. Just like Catherine II, Frederick recognized the educational skills the Jesuits had as an asset for the nation. He was interested in attracting a diversity of skills to his country, whether from Jesuit teachers, Huguenot citizens, or Jewish merchants and bankers; the best known were the Rothschilds of Frankfurt, who eventually attained the status of court Bankers in Hesse-Kassel in 1795 after Frederick's passing. Nonetheless, Frederick wanted development throughout the country, specifically in areas that he judged as needing a particular kind of development. Thus, he accepted countless Protestant weavers from Bohemia, who were fleeing from the devoutly Catholic rule of Maria Theresa. Frederick granted the weavers freedom from taxes and military Service. As an Example of Frederick's practical-minded but not fully unprejudiced tolerance, Frederick wrote in his Testament politique that:

Frederick's goal was to modernize and unite his vulnerably disconnected lands; toward this end, he fought wars mainly against Austria, whose Habsburg dynasty reigned as Holy Roman Emperors almost continuously from the 15th century until 1806. Frederick established Prussia as the fifth and smallest European great power by using the resources his frugal father had cultivated.

An Example of the place that Frederick holds in history as a ruler is seen in Napoleon Bonaparte, who saw the Prussian king as the greatest tactical genius of all time; after Napoleon's victory of the Fourth Coalition in 1807, he visited Frederick's tomb in Potsdam and remarked to his officers, "Gentlemen, if this man were still alive I would not be here". Napoleon frequently "pored through Frederick's campaign narratives and had a statuette of him placed in his personal cabinet." Frederick and Napoleon are perhaps the most admiringly quoted military Leaders in Clausewitz' On War. More than Frederick's use of the oblique order, Clausewitz praised particularly the quick and skillful movement of his troops.

Historian Leopold von Ranke was unstinting in his praise of Frederick's "heroic life, inspired by great ideas, filled with feats of arms ... immortalized by the raising of the Prussian state to the rank of a power". Johann Gustav Droysen was even more favorable. Nationalist Historian Heinrich von Treitschke presented Frederick as the greatest German in centuries. Onno Klopp was one of the few German historians of the 19th century who denigrated and ridiculed Frederick. The Novelist Thomas Mann in 1914 also attacked Frederick, arguing – like Empress Maria Theresa – that he was a wicked man who robbed Austria of Silesia, precipitating the alliance against him. Nevertheless, with Germany humiliated after the World War, Frederick's popularity as a heroic figure remained high in Germany. Frederick's place in British historiography was established by Thomas Carlyle's History of Frederick the Great (8 vol. 1858–65), emphasizing the power of one great "hero" to shape history.

In the 21st century his reputation as a warrior remains strong among military historians. Historians in general continue to debate the issue of continuity versus innovation. How much of the king's achievement was based on developments already under way, and how much can be attributed to his initiative? How closely linked was he to The Enlightenment? Is the category of "enlightened absolutism" still useful for the scholar?

In 1933–45, the Nazis glorified Frederick as a precursor to Hitler and presented Frederick as holding out hope that another miracle would again save Germany at the last moment. Nevertheless, the nationalist (but anti-Nazi) Historian Gerhard Ritter condemned Frederick's brutal seizure in the first partition of Poland; however, he praised the results as beneficial to the Polish people. Ritter's biography of Frederick, published in 1936, was designed as a challenge to Nazi claims that there was a continuity between Frederick and Hitler. Dorpalen says "The book was indeed a very courageous indictment of Hitler's irrationalism and recklessness, his ideological fanaticism and insatiable lust for power."

The Great King (German: Der Große König) is a 1942 German drama film directed by Veit Harlan and starring Otto Gebühr. It depicts the life of Frederick the Great. It received the rare "Film of the Nation" distinction. Otto Gebühr also played the King in many other films.

Frederick's reputation was sharply downgraded after 1945 in both East and West Germany. His diminished legacy in Germany was due in part to the Nazis' fascination with him, to say nothing of his supposed connection with "Prussian militarism". Nonetheless, nowadays Frederick is generally held in high regard, especially for his statesmanship – and for his enlightened reforms that positively changed not only Germany but European society in general, allowing German intellectuals to assert that the revolutions in both France and America were to some extent "belated" attempts to "catch up with Prussia".

On the 205th anniversary of his death, on 17 August 1991, Frederick's casket lay in state in the court of honor at Sanssouci, covered by a Prussian flag and escorted by a Bundeswehr guard of honor. After nightfall, Frederick's body was finally laid to rest in the terrace of the vineyard of Sanssouci – in the still existing crypt he had built there – without pomp, in accordance with his will.

In the 2004 German film Der Untergang (Downfall), Adolf Hitler is shown sitting in a dark room forlornly gazing at a painting of Frederick, possibly a reference to the dictator's fading hopes for another Miracle of the House of Brandenburg. This is based on an incident witnessed by Rochus Misch.

The 2012 German made-for-television film Friedrich – ein deutscher König (Frederick – a German King) starred the actresses Katharina Thalbach and her daughter Anna Thalbach in the title roles as the old and young king respectively.

William Hogarth's painting The Toilette features a flautist (who stands next to a painting of Zeus, as an eagle, abducting Ganymede), which may be a satirical depiction of Frederick – thereby publicly outing him as a homosexual as early as 1744. Frederick certainly spent much of his time at Sanssouci, his favourite residence in Potsdam, in a circle that was exclusively male, though a number of his entourage were happily married. The palace gardens include a Temple of Friendship (built as a memorial to Wilhelmine), which celebrate the homoerotic attachments of Greek Antiquity, and which is decorated with portraits of Orestes and Pylades, amongst others. At Sanssouci Frederick entertained his most privileged guests, especially the French Philosopher Voltaire, whom he asked in 1750 to come to live with him. Their literary correspondence and friendship, which spanned almost 50 years, was marked by mutual intellectual fascination, and began as a flirtation. However, in person Frederick found Voltaire difficult to live with, and was often annoyed by Voltaire's many quarrels with his other friends. Voltaire's angry attack on Maupertuis, the President of Frederick's academy, in the form of Le Diatribe du Docteur Akakia provoked Frederick to burn the pamphlet publicly and put Voltaire under house arrest, after which Voltaire left Prussia.

Frederick the Great was keenly interested in land use, especially draining swamps and opening new farmland for colonizers who would increase the kingdom's food supply. He called it "peopling Prussia" (Peuplierungspolitik). About a thousand new villages were founded in his reign that attracted 300,000 immigrants from outside Prussia. He told Voltaire, "Whoever improves the soil, cultivates land lying waste and drains swamps, is making conquests from barbarism". Using improved Technology enabled him to create new farmland through a massive drainage program in the country's Oderbruch marsh-land. This program created roughly 60,000 hectares (150,000 acres) of new farmland, but also eliminated vast swaths of natural habitat, destroyed the region's biodiversity, and displaced numerous native plant and animal communities. Frederick saw as this project as the "taming" and "conquering" of nature, which, in its wild form, he regarded as "useless" and "barbarous"—an attitude that reflected his enlightenment-era, rationalist sensibilities. He presided over the construction of canals for bringing crops to market, and introduced new crops, especially the potato and the turnip, to the country. For this, he was sometimes called Der Kartoffelkönig (the Potato King).

On the other hand, while still considering the German culture of his time to be inferior to that of France or Italy, he did actually take an interest in its development. He thought that it had partly been hindered by the great wars of the 17th century (the Thirty Years' War, the Ottoman wars, the invasions of Louis XIV) but that with some time and effort, it could equal or even surpass that of its rivals. In his view, this would require a complete codification of the German language with the help of official academies, the emergence of talented classical German authors and extensive patronage of the arts from Germanic rulers. However, he did not expect to see this happen in his lifetime. His love for French culture was not without limits either. Frederick II was not appreciative of the luxury and extravagance of the French royal court, and he ridiculed German princes (especially Augustus III, Elector of Saxony) who mimicked the French by indulging in those pleasures. His own court remained quite Spartan, frugal and small, restricted to a limited circle of close friends- a layout similar to his father's court, though Frederick and his friends were far more cultured than Frederick william. Also, Frederick the Great was dismissive of the radical philosophy of later French thinkers such as Rousseau (though he in fact sheltered Rousseau from persecution for a number of years), and grew to believe that the French cultural golden age was drawing to a close.

Frederick in German memory became a great national hero in the 19th century. Many Germans said he was the greatest monarch in modern history. German historians often made him the romantic model of a glorified warrior, praising his leadership, administrative efficiency, devotion to duty and success in building up Prussia to a leading role in Europe.