Thornton was born in Canada and resides in London. Her education comprises a BA in the History of Art from Concordia University, Montreal, and a PhD in the Sociology of Music from Strathclyde University, Glasgow.McGlone, Jackie. (30 September 2008). 'Sarah Thornton-- Swimming in shark-infested waters'. The Scotsman. Retrieved 28 June 2009. Her academic posts have included a full-time lecturership at the University of Sussex, and a period as Visiting Research Fellow at Goldsmiths, University of London. Thornton worked for one year as a brand planner in a London advertising agency. She is the chief writer about contemporary art for The Economist.

Club Cultures analyses the "hipness" of British rave culture and coins the term, "subcultural capital", an adaption of Pierre Bourdieu's concept as outlined in many works including Distinction. The study responds to earlier works such as Dick Hebdige's Subculture: The Meaning of Style.

Local micro-media like flyers and listings are means by which club organizers bring the crowd together. Niche media like the music press construct subcultures as much as they document them. National mass media, such as tabloids, develop youth movements as much as they distort them. Contrary to youth subcultural ideologies, "subcultures" do not germinate from a seed and grow by force of their own energy into mysterious ‘movements’ only to be belatedly digested by the media. Rather, media and other culture industries are there and effective right from the start. They are central to the process of subcultural formation.Thornton, Sarah. (1996). Club Cultures : Music, Media, and Subcultural Capital. Hanover: University Press of New England, p. 117.

Thornton co-edited the first edition of The Subcultures Reader with Ken Gelder.

Thornton has written about the contemporary art market and art world for publications including The Economist, The Sunday Times Magazine , The Art Newspaper, Artforum.com, The New YorkerThornton, Sarah. (19 March 2007). 'Letter from London: Reality Art Show'. The New Yorker. Retrieved 28 June 2009., The TelegraphThornton, Sarah. (3 October 2008). 'Is art the new gold?'. The Telegraph. Retrieved 28 June 2009., The GuardianThornton, Sarah. (16 October 2008). 'If the work is free, is it art?'. The Guardian. Retrieved 28 June 2009., and The New Statesman.Thornton, Sarah. (23 October 2008). 'Bye-bye to bling for billionaires'. New Statesman. Retrieved 28 June 2009.

Her book Seven Days in the Art World was published in 2008.

Her book Club Cultures: Music, Media, and Subcultural Capital is described by Stuart Hall and Tony Jefferson in Resistance Through Rituals as "theoretically innovative" and "conceptually adventurous".Hall, Stuart and Jefferson, Tony (Eds). (2006). Resistance Through Rituals (2nd ed.). Routledge: London, pp. xix-xx.

In the New York Times, Karen Rosenberg said that Seven Days in the Art World "was reported and written in a heated market, but it is poised to endure as a work of sociology...[Thornton] pushes her well-chosen subjects to explore the questions ‘What is an artist?’ and ‘What makes a work of art great?’”

In the UK, Ben Lewis wrote in The Sunday Times that Seven Days was "a Robert Altmanesque panorama of...the most important cultural phenomenon of the last ten years” While Peter Aspden argued in the Financial Times that “[Thornton] does well to resist the temptation to draw any glib, overarching conclusions. There is more than enough in her rigorous, precise reportage for the reader to make his or her own connections.”

Alastair Sooke in The Telegraph wrote, "She describes the excesses of today's art world with energy, clarity and panache, but in the final reckoning, she doesn't actually dig up that much dirt. We get a clear sense of quackery and monstrous egos, but the art world's murkier goings-on are rarely illuminated."Sooke, Alastair. (22 October 2008). Review: Seven Days in the Art World by Sarah Thornton. The Telegraph. http://www.telegraph.co.uk/culture/books/non_fictionreviews/3562431/Review-Seven-Days-in-the-Art-World-by-Sarah-Thornton.html . Retrieved 12 July 2009. Critic Matthew Collings said that Thornton is "not a seer, she's without a vision of how things could be different." He concluded, "Thornton gets to the heart of the problem of art-culture, which is that art has become trivial, whereas in previous eras it had some dignity. But she's too wrapped up in playing a role to realise it."Collings, Matthew. (18 October 2008). You've been framed. The Guardian. http://www.guardian.co.uk/books/2008/oct/18/art1 . Retrieved 12 July 2009.

András Szántó reviewed Seven Days in the Art World: “Underneath [the book's] glossy surface lurks a sociologist’s concern for institutional narratives as well as the ethnographer’s conviction that entire social structures can be apprehended in seemingly frivolous patterns of speech or dress.”Szántó, András. (29 October 2008). 'Message in a bottle'. Art World Salon. Retrieved 28 June 2009. In interview, R.J. Preece wrote, "I think Seven Days in the Art World might be the most important book on contemporary art of this time as it makes the art world more transparent, and might lead to reform."Preece, R.J. (15 June 2009). The Sociologist: Sarah Thornton and Seven Days in the Art World. Art, Design and Publicity. http://www.artdesigncafe.com/Art-Design-Publicity-mag-Sarah-Thornton-Seven-Days-in-the-Art-World-1-1-2009 . Retrieved 2 October 2009.

On 26 September 2009, The Telegraph published an apology to Thornton concerning a book review by Lynn Barber from 1 November 2008. Barber claimed she was not interviewed by Thornton for Seven Days; the apology indicated that in fact she was.(26 September 2009). Sarah Thornton - an apology. The Telegraph. Retrieved 2 January 2010. The following month, the Press Gazette reported that a judge had struck out The Telegraph's defence of fair comment regarding the accusation of "copy approval", another factual error in the book review. (16 November 2009). Judge strikes out fair comment defence in Lynn Barber book review, Press Gazette. Retrieved 2 January 2010. On 16 June 2010, Justice Tugendhat dismissed the claim for libel against the Telegraph and declared that the accusation of "copy approval" was "not capable of meaning that Dr Thornton had done anything which in ordinary language could be highly reprehensible, or reprehensible at all" (16 June 2010). Lynn Barber libel victory 'raises bar' for claimants, Press Gazette. Retrieved 18 June 2010. The case is proceeding through a claim in malicious falsehood.(29 June 2010). Barber legal case to continue despite defamation ruling, Press Gazette. Retrieved 13 July 2010.