Thackeray, an only child, was born in Calcutta, British India, where his father, Richmond Thackeray (1 September 1781 – 13 September 1815), was secretary to the Board of Revenue in the British East India Company. His mother, Anne Becher (1792–1864), was the second daughter of Harriet Becher and John Harman Becher, who was also a secretary (writer) for the East India Company.

Thackeray's mother, Anne Becher (born 1792), was "one of the reigning beauties of the day" and a daughter of John Harmon Becher, Collector of the South 24 Parganas district (d. Calcutta, 1800), of an old Bengal civilian family "noted for the tenderness of its women". Anne Becher, her sister Harriet and their widowed mother, also Harriet, had been sent back to India by her authoritarian guardian grandmother, Ann Becher, in 1809 on the Earl Howe. Anne's grandmother had told her that the man she loved, Henry Carmichael-Smyth, an ensign in the Bengal Engineers whom she met at an Assembly Ball in 1807 in Bath, had died, while he was told that Anne was no longer interested in him. Neither of these assertions was true. Though Carmichael-Smyth was from a distinguished Scottish military family, Anne's grandmother went to extreme lengths to prevent their marriage. Surviving family letters state that she wanted a better match for her granddaughter.

Thackeray's father, Richmond Thackeray, was born at South Mimms and went to India in 1798 at age sixteen as a Writer (civil servant) with the East India Company. Richmond fathered a daughter, Sarah Redfield, in 1804 with Charlotte Sophia Rudd, his possibly Eurasian mistress, and both mother and daughter were named in his will. Such liaisons were Common among gentlemen of the East India Company, and it formed no bar to his later courting and marrying William's mother.

Anne Becher and Richmond Thackeray were married in Calcutta on 13 October 1810. Their only child, william, was born on 18 July 1811. There is a fine miniature portrait of Anne Becher Thackeray and william Makepeace Thackeray, aged about two, done in Madras by George Chinnery c. 1813.

William Makepeace Thackeray (/ˈθækəri/; 18 July 1811 – 24 December 1863) was a British Novelist and author. He is known for his satirical works, particularly Vanity Fair, a panoramic portrait of English society.

Anne's family's deception was unexpectedly revealed in 1812, when Richmond Thackeray unwittingly invited the supposedly dead Carmichael-Smyth to dinner. Five years later, after Richmond had died of a fever on 13 September 1815, Anne married Henry Carmichael-Smyth, on 13 March 1817. The couple moved to England in 1820, after having sent william off to school there more than three years earlier. The separation from his mother had a traumatic effect on the young Thackeray, which he discussed in his essay "On Letts's Diary" in The Roundabout Papers.

One of his earliest works, "Timbuctoo" (1829), contains a burlesque upon the subject set for the Cambridge Chancellor's Medal for English Verse (the contest was won by Tennyson with "Timbuctoo"). Thackeray's writing career really began with a series of satirical sketches now usually known as The Yellowplush Papers, which appeared in Fraser's Magazine beginning in 1837. These were adapted for BBC Radio 4 in 2009, with Adam Buxton playing Charles Yellowplush.

Thackeray's years of semi-idleness ended after he married, on 20 August 1836, Isabella Gethin Shawe (1816–1894), second daughter of Isabella Creagh Shawe and Matthew Shawe, a colonel who had died after distinguished Service, primarily in India. The Thackerays had three children, all girls: Anne Isabella (1837–1919), Jane (who died at eight months old) and Harriet Marian (1840–1875), who married Sir Leslie Stephen, Editor, biographer and Philosopher.

Thackeray now began "writing for his life", as he put it, turning to journalism in an effort to support his young family. He primarily worked for Fraser's Magazine, a sharp-witted and sharp-tongued conservative publication for which he produced art criticism, short fictional sketches, and two longer fictional works, Catherine and The Luck of Barry Lyndon. Between 1837 and 1840 he also reviewed books for The Times. He was also a regular contributor to The Morning Chronicle and The Foreign Quarterly Review. Later, through his connection to the Illustrator John Leech, he began writing for the newly created magazine Punch, in which he published The Snob Papers, later collected as The Book of Snobs. This work popularised the modern meaning of the word "snob". Thackeray was a regular contributor to Punch between 1843 and 1854.

Between May 1839 and February 1840 Fraser's published the work sometimes considered Thackeray's first novel, Catherine. Originally intended as a satire of the Newgate school of crime fiction, it ended up being more of a picaresque tale. He also began work, never finished, on the novel later published as A Shabby Genteel Story.

In the early 1840s Thackeray had some success with two travel books, The Paris Sketch Book and The Irish Sketch Book, the latter marked by hostility to Irish Catholics. However, as the book appealed to British prejudices, Thackeray was given the job of being Punch's Irish expert, often under the pseudonym Hibernis Hibernior. It was Thackeray, in other words, who was chiefly responsible for Punch's notoriously hostile and condescending depictions of the Irish during the Irish Famine (1845–51).

In The Luck of Barry Lyndon, a novel serialised in Fraser's in 1844, Thackeray explored the situation of an outsider trying to achieve status in high society, a theme he developed more successfully in Vanity Fair with the character of Becky Sharp, the artist's daughter who rises nearly to the heights by manipulating the other characters.

She eventually deteriorated into a permanent state of detachment from reality. Thackeray desperately sought cures for her, but nothing worked, and she ended up in two different asylums in or near Paris until 1845, after which Thackeray took her back to England, where he installed her with a Mrs Bakewell at Camberwell. Isabella outlived her husband by 30 years, in the end being cared for by a family named Thompson in Leigh-on-Sea at Southend until her death in 1894. After his wife's illness Thackeray became a de facto widower, never establishing another permanent relationship. He did pursue other women, however, in particular Mrs Jane Brookfield and Sally Baxter. In 1851 Mr Brookfield barred Thackeray from further visits to or correspondence with Jane. Baxter, an American twenty years Thackeray's junior whom he met during a lecture tour in New York City in 1852, married another man in 1855.

Thackeray achieved more recognition with his Snob Papers (serialised 1846/7, published in book form in 1848), but the work that really established his fame was the novel Vanity Fair, which first appeared in serialised instalments beginning in January 1847. Even before Vanity Fair completed its serial run Thackeray had become a Celebrity, sought after by the very lords and ladies whom he satirised. They hailed him as the equal of Dickens.

He remained "at the top of the tree", as he put it, for the rest of his life, during which he produced several large novels, notably Pendennis, The Newcomes and The History of Henry Esmond, despite various illnesses, including a near-fatal one that struck him in 1849 in the middle of writing Pendennis. He twice visited the United States on lecture tours during this period. Thackeray also gave lectures in London on the English humorists of the eighteenth century, and on the first four Hanoverian monarchs. The latter series was published in book form as The Four Georges.

In 1860 Thackeray became Editor of the newly established Cornhill Magazine, but he was never comfortable in the role, preferring to contribute to the magazine as the Writer of a column called "Roundabout Papers".

Thackeray's health worsened during the 1850s and he was plagued by a recurring stricture of the urethra that laid him up for days at a time. He also felt that he had lost much of his creative impetus. He worsened matters by excessive eating and drinking, and avoiding exercise, though he enjoyed riding (he kept a horse). He has been described as "the greatest literary glutton who ever lived". His main activity apart from writing was "guttling and gorging". He could not break his addiction to spicy peppers, further ruining his digestion. On 23 December 1863, after returning from dining out and before dressing for bed, he suffered a stroke. He was found dead in his bed the following morning. His death at the age of fifty-two was entirely unexpected, and shocked his family, his friends and the reading public. An estimated 7,000 people attended his funeral at Kensington Gardens. He was buried on 29 December at Kensal Green Cemetery, and a memorial bust sculpted by Marochetti can be found in Westminster Abbey.

In 1887 the Royal Society of Arts unveiled a blue plaque to commemorate Thackeray at the house at 2 Palace Green, London, that had been built for him in the 1860s. It is now the location of the Israeli Embassy.

Also notable among the later novels is The History of Henry Esmond, in which Thackeray tried to write a novel in the style of the eighteenth century, a period that held great appeal for him. About this novel, there have been found evident analogies—in the fundamental structure of the plot; in the psychological outlines of the main characters; in frequent episodes; and in the use of metaphors—to Ippolito Nievo's "Confessions of an Italian". Nievo wrote his novel during his stay in Milan where, in the “Ambrosiana” library, “The History of Henry Esmond” was available, just published.