Elizabeth was born at Kolomenskoye, near Moscow, on 18 December 1709 (O.S.), the daughter of Peter the Great, Tsar of Russia, by his second wife, Catherine I. Catherine had been a maid in the household of Peter the Great and, although no documentary record exists, they are said to have married secretly at the Cathedral of the Holy Trinity in St. Petersburg at some point of time between 23 October and 1 December 1707. Peter valued Catherine and married her again (this time officially) at Saint Isaac's Cathedral in St. Petersburg on 9 February 1712. On this day, the two children previously born to them (Anna and Elizabeth) were legitimized by their father. The circumstances of Elizabeth's birth would later be used by her political opponents to challenge her right to the throne on grounds of illegitimate birth.

Of the twelve children born to Peter and Catherine (five sons and seven daughters), only two daughters, Anna (b. 1708) and Elizabeth (b. 1709,) survived to adulthood. Both of them were given the title of Tsarevna (“princess”) on 6 March 1711, and of Tsesarevna (“crown princess”) on 23 December 1721. They had one older surviving sibling, crown Prince Alexei Petrovich, who was Peter's son by his first wife Eudoxia Lopukhina, a noblewoman.

So long as Aleksandr Danilovich Menshikov remained in power (until September 1727) the government of Elizabeth's adolescent half-nephew Peter II (reigned 1727–1730) treated her with liberality and distinction. The Dolgorukovs, an ancient boyar family, deeply resented Menshikov. With Peter II's attachment to Prince Ivan Dolgorukov, and with two of their family members on the Supreme State Council, they had the leverage for a successful coup. Menshikov was arrested, stripped of all his honours and properties and exiled to northern Siberia where he died in November 1729. The Dolgorukovs hated the memory of Peter the Great and practically banished his daughter from Court.

During the reign of her cousin, Anna (1730–1740), Elizabeth was gathering support in the background. After the death of Empress Anna, the regency of Anna Leopoldovna for the infant Ivan VI was marked by high taxes and economic problems. Elizabeth, being the daughter of Peter the Great, enjoyed much support from the Russian guards regiments. The French ambassador in St. Petersburg, the marquis de La Chétardie was deeply involved in planning a coup to depose the regent Anna whose anti-French foreign policy was opposed to the interests of France, and bribed numerous officers in the Imperial Guard to support the coup. Elizabeth often visited the elite Guards regiments, marking special events with the officers, and acting as godmother to their children.

The guards repaid her kindness when, on the night of 25 November 1741, Elizabeth seized power with the help of the Preobrazhensky Regiment. Arriving at the regimental headquarters wearing a warrior's metal breastplate over her dress and grasping a silver cross she challenged them: "Whom do you want to serve: me, your natural sovereign, or those who have stolen my inheritance?" Won over, the regiment marched to the Winter Palace and arrested the infant Emperor, his parents, and their own lieutenant-colonel, Count von Munnich. It was a daring coup and, amazingly, succeeded without bloodshed. Elizabeth had vowed that if she became Empress she would not sign a single death sentence, an extraordinary promise for the time but one which she kept throughout her life.

The young Peter had lost his mother, Elizabeth's sister Anna, at three months old and his father at the age of eleven. Elizabeth invited her young nephew to Saint Petersburg, where he was received into the Orthodox Church and proclaimed heir on 7 November 1742. Elizabeth gave him at once Russian tutors. Keen to see the dynasty secured Elizabeth settled on Princess Sophie of Anhalt-Zerbst as a bride for her nephew. Incidentally, Sophie's mother, Joanna Elisabeth of Holstein-Gottorp, was a sister of Elizabeth's own fiancé who had died before the wedding. On her conversion to the Russian Orthodox Church Sophie was given the name Catherine in memory of Elizabeth's mother. The marriage took place on 21 August 1745. Nine years later, a son, the Future Paul I, was finally born on 20 September 1754.

Elizabeth abolished the cabinet council system that had been used under Anna, and reconstituted the senate as it had been under Peter the Great with the chiefs of the departments of state (none of them Germans) attending. Her first task after this was to address the war with Sweden. On 23 January 1743 direct negotiations between the two powers were opened at Åbo (Turku). In the Treaty of Åbo, on 7 August 1743, Sweden ceded to Russia all of southern Finland east of the Kymmene River, which became the boundary between the two states. The treaty also gave Russia the fortresses of Villmanstrand and Fredrikshamn.

Ultimately, the minister's strong support from Elizabeth prevailed. His faultless diplomacy, and an auxiliary Russian corps of 30,000 men sent to the Rhine, greatly accelerated the peace negotiations leading to the Treaty of Aix-la-Chapelle (18 October 1748). By sheer tenacity of purpose, Bestuzhev had extricated his country from the Swedish imbroglio; reconciled his imperial mistress with the courts of Vienna and London; enabled Russia to assert herself effectually in Poland, Turkey and Sweden; and isolated the King of Prussia by forcing him into hostile alliances. All this would have been impossible without the steady support of Elizabeth who trusted him completely in spite of the Chancellor's many enemies, most of whom were her personal friends.

Under the reign of Elizabeth, the Russian court was one of the most splendid in all Europe. Foreigners were amazed at the sheer luxury of the sumptuous balls and masquerades. The Russian court had steadily increased in importance throughout the 18th century and came to hold more cultural significance than many of its Western counterparts due its inclusive nature; any “well to do inhabitants” were welcome at Court. The Court, like most Imperial Courts, was considered a reflection of the ruler at its center and Elizabeth was said to be “the laziest, most extravagant and most amorous of sovereigns.” Elizabeth was intelligent but lacked the discipline and early education necessary to flourish as an intellectual; she found the reading of secular literature to be “injurious to health.” She was kind and warm-hearted for the emotion's sake alone, once going so far as to offer to Finance the reconstruction of Lisbon after the 1755 earthquake destroyed the Portuguese city despite having and wanting no diplomatic relationship with the nation. She hated bloodshed and conflict and went to great lengths to alter the Russian system of punishment, even outlawing capital punishment. Even in court this peacemaker spirit made itself evident. According to Historian Robert Nisbet Bain, it was one of Elizabeth’s “chief glories that, so far as she was able, she put a stop to that mischievous contention of rival ambitions at Court, which had disgraced the reigns of Peter II, Anne and Ivan VI, and enabled foreign powers to freely interfere in the domestic affairs of Russia.” She was also deeply religious, passing several pieces of legislation that undid much of the work her father had done to limit the power of the church. Yet of all her various characteristics manifested in the structure of Court life the most evident were her extravagance, her Vanity, and her gaiety and playful nature.

The great event of Elizabeth's later years was the Seven Years' War. Elizabeth regarded the Convention of Westminster (16 January 1756) in which Great Britain and Prussia agreed to unite their forces to oppose the entry of or the passage through Germany of troops of every foreign power, as utterly subversive of the previous conventions between Great Britain and Russia. Elizabeth sided against Prussia over a personal dislike of Frederick the Great. She wanted him reduced within proper limits so that he might no longer be a danger to the empire. Elizabeth acceded to the Treaty of Versailles, thus entering into an alliance with France and Austria against Prussia. On 17 May 1757 the Russian army, 85,000 strong, advanced against Königsberg.

The serious illness of the Empress, which began with a fainting-fit at Tsarskoe Selo (19 September 1757), the fall of Bestuzhev (21 February 1758) and the cabals and intrigues of the various foreign powers at Saint Petersburg did not interfere with the progress of the war. The crushing defeat of Kunersdorf (12 August 1759) at last brought Frederick to the verge of ruin. From that day, he despaired of success, but he was saved for the moment by the jealousies of the Russian and Austrian commanders, which ruined the military plans of the allies.

However, on 14 February 1758, Bestuzhev was removed from office. The Future Catherine II recorded, "He was relieved of all his decorations and rank, without a soul being able to reveal for what crimes or transgressions the first gentleman of the Empire was so despoiled, and sent back to his house as a prisoner." No specific crime was ever pinned on Bestuzhev. Instead, it was inferred that he had attempted to sow discord between the Empress and her heir and his consort. Enemies of pro-Austrian Bestuzhev were his rivals; the Shuvalov family, Vice-Chancellor Mikhail Vorontsov, and the French ambassador.

From the end of 1759 to the end of 1761, the firmness of the Russian Empress was the one constraining political force that held together the heterogeneous, incessantly jarring elements of the anti-Prussian combination. From the Russian point of view, her greatness as a stateswoman consists in her steady appreciation of Russian interests, and her determination to promote them at all hazards. She insisted throughout that the King of Prussia must be rendered harmless to his neighbors for the Future and that the only way to do so was to reduce him to the rank of a Prince-Elector.

Simultaneously, Elizabeth had conveyed to Louis XV a confidential letter in which she proposed the signature of a new treaty of alliance of a more comprehensive and explicit nature than the preceding treaties between the two powers without the knowledge of Austria. Elizabeth's object in the mysterious negotiation seems to have been to reconcile France and Great Britain, in return for which signal Service France was to throw all her forces into the German war. This project, which lacked neither ability nor audacity, foundered upon Louis XV's invincible jealousy of the growth of Russian influence in Eastern Europe and his fear of offending the Porte. It was finally arranged by the allies that their envoys at Paris should fix the date for the assembling of a peace congress and that in the meantime, the war against Prussia should be vigorously prosecuted. In 1760 a Russian flying column briefly occupied Berlin. Russian victories placed Prussia in serious danger.

In the late 1750s Elizabeth's health started to decline. She began to suffer a series of dizzy spells and refused to take the prescribed medicines. She forbade the word "death" in her presence. Elizabeth suffered a stroke on Christmas eve 1761. Knowing that she was dying, Elizabeth used her last remaining strength to make her confession, to recite with her confessor the prayer for the dying and to say farewell to those few people who wished to be with her, including Peter and Catherine and Counts Alexei and Kirill Razumovsky. The Empress died the next day, 25 December 1761. For her lying in state she was dressed in a shimmering silver dress, she was beautiful in death as she had been in life. She was buried in the Peter and Paul Cathedral in Saint Petersburg on 3 February 1762 after six weeks lying in state.

The campaign of 1761 was almost as abortive as the campaign of 1760. Frederick acted on the defensive with consummate skill, and the capture of the Prussian fortress of Kolberg on Christmas Day 1761, by Rumyantsev, was the sole Russian success. Frederick, however, was now at the last gasp. On 6 January 1762, he wrote to Count Karl-Wilhelm Finck von Finckenstein, "We ought now to think of preserving for my nephew, by way of negotiation, whatever fragments of my territory we can save from the avidity of my enemies," which meant, if words mean anything, that he was resolved to seek a soldier's death on the first opportunity. A fortnight later, he wrote to Prince Ferdinand of Brunswick, "The sky begins to clear. Courage, my dear fellow. I have received the news of a great event." The Miracle of the House of Brandenburg that snatched him from destruction was the death of the Russian Empress, on 5 January 1762 (N.S.).

Despite Elizabeth’s volatile, often violent reactions in regards to her appearance, the Empress was ebullient in most other matters particularly when it came to Court entertainment. Elizabeth was renowned throughout and beyond Russia for the balls she held and her fierce commitment to the arts, particularly music, theater, and architecture. It is reported that Elizabeth threw two balls a week. One would be a large event with an average of 800 guests in attendance, most of whom were the nation’s leading merchants, members of the lower nobility, and guards stationed in and around the city of the event. The other ball was a much smaller affair reserved for Elizabeth’s closest friends as well as members of the highest echelons of nobility. These smaller gatherings began as masked balls but evolved into the famous Metamorphoses balls by 1744. At these Metamorphoses balls, guests were expected to dress as the opposite sex, with Elizabeth often dressing up as Cossack or carpenter in honor of her father. The costumes not permitted at the event were those of pilgrims and harlequins, which the Empress considered profane and indecent respectively. Most members of court thoroughly disliked these balls since most looked ridiculous but Elizabeth adored them. As Catherine the Great’s advisor Potemkin posited, this adoration was due to the fact that she was “the only woman who looked truly fine, and completely a man… As she was tall and powerful, male attire suited her.” Though the balls were by far her most personally beloved and lavish events, Elizabeth often threw children’s birthday parties and wedding receptions for those affiliated with her Court, going so far as to provide dowries for each of her ladies-in-waiting. The other court pastimes most enjoyed by Elizabeth and therefore most revered in Court were theatre, music, and architecture. The Empress had a longstanding love of theatre and had a stage erected in the palace to enjoy the countless performances she sanctioned. Though countless domestic and foreign works were shown, the French plays quickly became the most popular, often being performed twice a week. In tandem with Elizabeth’s love of theatre, music came to be of high importance in Court. Many attribute its popularity to Elizabeth’s relationship with Alexei Razumovsky, a Ukrainian Cossack and the supposed husband of the Empress, who reportedly relished music. Regardless of the reasoning behind its introduction, Elizabeth transformed “her court into the country’s leading musical center.” She would spare no expense in its regard, importing leading musical talents from Germany, France, and Italy. As to the Empress’ love of architecture, she financed many construction projects during her reign. Her most famous creations were the Winter Palace, which she commissioned and oversaw the construction of but died before its completion, and the Smolny Convent. The Convent, built when Elizabeth considered becoming a nun, was one of the many religious buildings erected at her behest, using the nation's funds (rather than those of the church). According to Robert Nisbet Bain, “No other Russian sovereign ever erected so many churches.”