Sophia Charlotte was born on 19 May 1744. She was the youngest daughter of Duke Charles Louis Frederick of Mecklenburg-Strelitz (1708–1752; known as "Prince of Mirow") and of his wife Princess Elizabeth Albertine of Saxe-Hildburghausen (1713–1761). Mecklenburg-Strelitz was a small north-German duchy in the Holy Roman Empire.

The Queen died in the presence of her eldest son, the Prince Regent, who was holding her hand as she sat in an armchair at the family's country retreat, Dutch House in Surrey (now known as Kew Palace). She was buried at St George's Chapel, Windsor Castle. Her husband died just over a year later. She is the second longest-serving consort in British history (after the present Duke of Edinburgh), having served as such from her marriage (on 8 September 1761) to her death (17 November 1818), a total of 57 years and 70 days.

St. James's Palace was the official residence of the royal couple, but the king had recently purchased a nearby property, Buckingham House, located at the western end of St. James's Park. The new property was relatively more private and compact and stood amid rolling parkland not far from St. James's palace. Around 1762, the King and Queen moved to this residence, which was originally intended as a private retreat. The Queen came to favor this residence greatly, spending much of her time there, so that it came to be known as The Queen's House. Indeed, in 1775, an Act of Parliament settled the property on Queen Charlotte in exchange for her rights to Somerset House (see Old and New London below). As many as 14 of her 15 children were born in Buckingham House. However, St. James's Palace remained the official and ceremonial royal residence.

In April 1764, Wolfgang Amadeus Mozart, then aged eight, arrived in Britain with his family as part of their grand tour of Europe and remained until July 1765. The Mozarts were summoned to court on 19 May and played before a limited circle from six to ten o'clock. Johann Christian Bach, eleventh son of the great Johann Sebastian Bach, was then music-master to the Queen. He put difficult works of Handel, J. S. Bach, and Carl Friedrich Abel before the boy: he played them all at sight, and those present were quite amazed. Afterwards, the young Mozart accompanied the Queen in an aria which she sang, and played a solo work on the flute. On 29 October, the Mozarts were in town again, and were invited to court to celebrate the fourth anniversary of the King's accession. As a memento of the royal favour, Leopold Mozart published six sonatas composed by Wolfgang, known as Mozart's Opus 3, that were dedicated to the Queen on 18 January 1765, a dedication she rewarded with a present of 50 guineas.

Rutgers, The State University of New Jersey, was chartered in 1766 as Queen's College, in reference to Queen Charlotte. Despite the American Revolution, it was not renamed until 1825, in honor of Henry Rutgers, a revolutionary war officer and college benefactor. The link to Charlotte is retained by its oldest extant building, Old Queen's (built 1809–1823), and the city block that forms the historic core of the university, Queen's Campus.

The King enjoyed country pursuits and riding and preferred to keep his family's residence as much as possible in the then rural towns of Kew and Richmond-upon-Thames. He favoured an informal and relaxed domestic life, to the dismay of some courtiers more accustomed to displays of grandeur and strict protocol. Lady Mary Coke was indignant on hearing in July 1769 that the King, the Queen, her visiting brother Prince Ernest and Lady Effingham had gone for a walk through Richmond town by themselves without any servants. "I am not satisfied in my mind about the propriety of a Queen walking in town unattended."

From 1778, the Royal family spent much of their time at a newly constructed residence, Queen's Lodge at Windsor, opposite Windsor Castle, in Windsor Great Park where the King enjoyed hunting deer. The Queen was responsible for the interior decoration of their new residence, described by friend of the Royal Family and diarist Mary Delany: "The entrance into the first room was dazzling, all furnished with beautiful Indian paper, chairs covered with different embroideries of the liveliest colours, glasses, tables, sconces, in the best taste, the whole calculated to give the greatest cheerfulness to the place."

Charlotte did have some influence on political affairs through the King, an influence she was not considered to abuse. Her influence was discreet and indirect, as demonstrated in the correspondence with her brother Charles. She used her closeness with George III to keep herself informed and make recommendations for offices. Apparently, her recommendations were not direct, as she on one occasion, in 1779, asked her brother Charles to burn her letter, because the King suspected that a person she had recently recommended for a post was the client of a woman who sold offices. Charlotte particularly interested herself in German issues. She took an interest in the War of the Bavarian Succession of 1778, and it is possible that it was due to her efforts that the King supported British intervention in that war in 1785.

Up until 1788, portraits of Charlotte often depict her in maternal poses with her children, and she looks young and contented; however, in that year her husband fell seriously ill and became temporarily insane. It is now thought that the King was suffering from porphyria, but at the time the cause of the King's illness was unknown. Sir Thomas Lawrence's portrait of her at this time marks a transition point, after which she looks much older in her portraits; the Assistant Keeper of Charlotte's Wardrobe, Mrs. Papendiek, wrote that the Queen was "much changed, her hair quite grey".

The French Revolution of 1789 probably added to the strain that Charlotte felt. Queen Charlotte and Queen Marie Antoinette of France and Navarre kept a close relationship. Charlotte was 11 years older than Marie Antoinette, yet they shared many interests, such as their love of music and the arts, in which they both enthusiastically took an interest. Never meeting face to face, they kept their friendship to pen and paper. Marie Antoinette confided in Charlotte upon the outbreak of the French Revolution. Charlotte had organized apartments to be prepared and ready for the refugee royal family of France to occupy. After the execution of Marie Antoinette and the bloody events that followed, Charlotte was said to have been shocked and overwhelmed that such a thing could happen to a kingdom, and at Britain's doorstep.

As the King gradually became permanently insane, the Queen's personality altered: she developed a terrible temper, sank into depression, no longer enjoyed appearing in public, not even at the musical concerts she had so loved, and her relationships with her adult children became strained. From 1792, she found some relief from her worry about her husband by planning the gardens and decoration of a new residence for herself, Frogmore House, in Windsor Home Park. From 1804 onward, when the King displayed a declining mental health, Queen Charlotte slept in a separate bedroom, had her meals separated from him, and avoided seeing him alone. From this time, Charlotte cultivated a better relationship with her eldest son the Prince of Wales together with her daughters Princess Augusta and Princess Elizabeth, and her sons the Dukes of Clarence, Kent and Sussex, while her younger daughters as well as her other sons (the Dukes of York, Cumberland and Cambridge) supported their father.

The Queen's arms changed twice to mirror the changes in her husband's arms, once in 1801 and then again in 1816. A funerary hatchment displaying the Queen's full coat of arms painted in 1818, is on display at Kew Palace.

The queen founded orphanages, and in 1809 became the patron (providing new funding) of the General Lying-in Hospital, a hospital for expectant mothers. It was subsequently renamed as the Queen's Hospital, and is today the Queen Charlotte's and Chelsea Hospital. The education of women was of great importance to her, and she ensured that her daughters were better educated than was usual for young women of the day; however, she also insisted that her daughters live restricted lives close to their mother, and she refused to allow them to marry until they were well-advanced in years. As a result, none of her daughters had legitimate issue (one, Princess Sophia, may have had an illegitimate son).

After the onset of his permanent madness in 1811, George III was placed under the guardianship of his wife in accordance with the Regency Bill of 1789. She could not bring herself to visit him very often, due to his erratic behaviour and occasional violent reactions. It is believed she did not visit him again after June 1812. However, Charlotte remained supportive of her spouse as his illness, now believed to be porphyria, worsened in old age. While her son, the Prince Regent, wielded the royal power, she was her spouse's legal guardian from 1811 until her death in 1818. Due to the extent of the King's illness he was incapable of knowing or understanding that she had died.

During the Regency of her son, Queen Charlotte continued to fill her role as first lady in royal representation because of the estrangement of the Prince Regent and his spouse. As such, she functioned as the hostess by the side of her son at official receptions, such as the festivities given in London to celebrate the defeat of Emperor Napoleon in 1814. She also supervised the upbringing of Charlotte of Wales. During her last years, she was met with a growing lack of popularity and sometimes subjected to demonstrations. After having attended a reception in London on 29 April 1817, she was jeered by a crowd. She told the crowd that it was upsetting to be treated like that after such long Service.

Her eldest son, the Prince Regent, claimed Charlotte's jewels at her death, but the rest of her property was sold at auction from May to August 1819. Her clothes, furniture, and even her snuff were sold by Christie's. It is highly unlikely that her husband ever knew of her death. He died blind, deaf, lame and insane 14 months later.

Queen Charlotte was played by Helen Mirren in the 1994 film The Madness of King George.

In 2004, the Queen's Gallery at Buckingham Palace staged an exhibition illustrating George and Charlotte's enthusiastic arts patronage, which was particularly enlightened in contrast to that of earlier Hanoverian monarchs. It compared favorably to the adventuresome tastes of the King's father, Frederick, Prince of Wales.

In a 2009 episode of the PBS TV series, Frontline, Valdes speculated that Scottish Painter Allan Ramsay emphasized the Queen's alleged "mulatto" appearance in his portrait of her to support the anti-slave trade movement, and noted that Baron Stockmar had described the Queen as having a "mulatto face" in his autobiography and that other contemporary sources made similar observations.

Critics of Valdes's theory point out that Margarita's and Madragana's distant perch in the queen's family tree – nine and 15 generations removed, respectively – makes any African ancestry that they bequeathed to Charlotte negligible and even doubt whether Madragana was black. In addition, Charlotte shared descent from Alfonso and Madragana with a large proportion of Europe's royalty and nobility.