Smith was born Sadie Smith in the north-west London borough of Brent to a Jamaican mother, Yvonne Bailey, and an English father, Harvey Smith. At age 14, she changed her name to Zadie. Her mother grew up in Jamaica, and emigrated to England in 1969. Smith's parents divorced when she was a teenager. She has a half-sister, a half-brother, and two younger brothers (one is the rapper and stand-up comedian Doc Brown, and the other is the rapper Luc Skyz). As a child, Smith was fond of tap dancing, and in her teenage years, she considered a career in musical theatre. While at university, Smith earned money as a jazz singer, and wanted to become a journalist. Despite earlier ambitions, literature emerged as her principal interest.
Smith attended the local state schools, Malorees Junior School and Hampstead Comprehensive School, and King's College, Cambridge, where she studied English literature. In an interview with The Guardian in 2000, Smith corrected a newspaper assertion that she left Cambridge with a double First. "Actually, I got a Third in my Part Ones," she said.
Smith seems to have been rejected for a place in the Cambridge Footlights by the popular British comedy double act Mitchell and Webb, while all three were studying at Cambridge University in the 1990s.
At Cambridge, Smith published a number of short stories in a collection of new student writing called The Mays Anthology. They attracted the attention of a publisher, who offered her a contract for her first novel. Smith decided to contact a literary agent and was taken on by A. P. Watt. Smith returned to guest-edit the anthology in 2001.
Smith's début novel White Teeth was introduced to the publishing world in 1997, before it was completed. On the basis of a partial manuscript, an auction for the rights was begun; Hamish Hamilton won. Smith completed White Teeth during her final year at Cambridge. Published in 2000, the novel immediately became a best-seller. It was praised internationally and won a number of awards, among them the James Tait Black Memorial Prize, and the Betty Trask Award. The novel was adapted for television in 2002. Smith served as writer-in-residence at the ICA in London and subsequently published, as editor, an anthology of sex writing, Piece of Flesh, as the culmination of this role.
In interviews, Smith reported that the hype surrounding her first novel had caused her to suffer briefly from writer's block. Nevertheless, her second novel, The Autograph Man, was published in 2002 and was a commercial success, although it was not as well-received by critics as White Teeth had been.
After the publication of The Autograph Man, Smith visited the United States as a Fellow of the Radcliffe Institute for Advanced Study at Harvard University. She started work on a still-unreleased book of essays, The Morality of the Novel (a.k.a. Fail Better), in which she considers a selection of 20th-century writers through the lens of moral philosophy. Some portions of this book presumably appear in the essay collection Changing My Mind, published in November 2009.
Smith's third novel, On Beauty, was published in September 2005. It is set largely in and around Greater Boston. It attracted more acclaim than The Autograph Man: it was shortlisted for the Man Booker Prize, and won the 2006 Orange Prize for Fiction and the Anisfield-Wolf Book Awards.
Later in the same year, Smith published Martha and Hanwell, a book that pairs two short stories about two troubled characters, originally published in Granta and The New Yorker respectively. Penguin published Martha and Hanwell with a new introduction by the author as part of their pocket series to celebrate their 70th birthday. The first story, "Martha, Martha", deals with Smith's familiar themes of race and postcolonial identity, while "Hanwell in Hell" is about a man struggling to cope with the death of his wife. In December 2008 she guest-edited the BBC Radio 4 Today programme.
After teaching fiction at Columbia University School of the Arts, Smith joined New York University as a tenured professor of fiction in 2010.
Smith's novel NW was published in 2012. It is set in the Kilburn area of north-west London, the title being a reference to the local postcode, NW6. NW was shortlisted for the Royal Society of Literature Ondaatje Prize and the Women’s Prize for Fiction.
In 2015 it was announced that Smith, along with her husband Nick Laird, was writing the screenplay for a science fiction movie to be directed by French filmmaker Claire Denis. Smith later claimed that her involvement had been overstated and that she had simply helped to polish the English dialogue for the film.
Smith's fifth novel, Swing Time, was published in November 2016. It was long-listed for the Man Booker Prize 2017.
Between March and October 2011, Smith was the monthly New Books reviewer for Harper's Magazine. She is also a frequent contributor to The New York Review of Books. In 2010, The Guardian newspaper asked Smith for her "10 rules for writing fiction". Among them she declared: "Tell the truth through whichever veil comes to hand – but tell it. Resign yourself to the lifelong sadness that comes from never being satisfied."
Smith met Nick Laird at Cambridge University. They married in 2004 in the Chapel of King's College, Cambridge. Smith dedicated On Beauty to "my dear Laird". The couple lived in Monti, Rome, Italy, from November 2006 to 2007, and are now based between New York City and Queen's Park, London. They have two children, Katherine (Kit) and Harvey (Hal).Smallwood, Christine (November 2012). "Mental weather: the many voices of Zadie Smith". Reviews. Harper's Magazine. 325 (1950): 86–90. Review of NW.White Teeth: won the Whitbread First Novel Award, the Guardian First Book Award, the James Tait Black Memorial Prize, and the Commonwealth Writers’ First Book Award. Included on Time magazine's 100 best English-language novels published from 1923 to 2005The Autograph Man: won the Jewish Quarterly Wingate Literary PrizeOn Beauty: won the Commonwealth Writers’ Best Book Award (Eurasia Section), and the Orange Prize for Fiction; shortlisted for the Man Booker PrizeNW: shortlisted for the Royal Society of Literature Ondaatje Prize and the Women's Prize for FictionGranta′s Best of Young British Novelists, 2003 and 20132016 Welt-Literaturpreis2017 Langston Hughes Medal