Ellis' first novel, Less Than Zero, a tale of disaffected, rich teenagers of Los Angeles, was praised by critics and sold well (50,000 copies in its first year). He moved back to New York City in 1987 for the publication of his second novel, The Rules of Attraction, which follows a group of sexually promiscuous college students, and sold fairly well, though Ellis admits he felt he had "fallen off", after the novel failed to match the success of his debut effort. His most controversial work is the graphically violent American Psycho. The book was intended to be published by Simon & Schuster, but they withdrew after external protests from groups such as the NOW and many others due to the allegedly misogynistic nature of the book. The novel was later published by Vintage. Some consider this novel, whose protagonist, Patrick Bateman, is both a cartoonishly materialistic yuppie and a serial killer, to be an example of transgressive art. American Psycho has achieved considerable cult status.

His collection of short stories, The Informers, was published in 1994. It contains vignettes of wayward Los Angeles characters ranging from rock stars to vampires, mostly written while Ellis was in college, and so has more in common with the style of Less Than Zero. Ellis has said that the stories in The Informers were collected and released only to fulfill a contractual obligation after discovering that it would take far longer to complete his next novel than he'd intended. After years of struggling with it, Ellis released his fourth novel Glamorama in 1998. Glamorama is set in the world of high fashion, following a male model who becomes entangled in a bizarre terrorist organization composed entirely of other models. The book plays with themes of media, celebrity, and political violence, and like its predecessor American Psycho it uses surrealism to convey a sense of postmodern dread. Ellis's novel Lunar Park (2005), uses the form of a celebrity memoir to tell a ghost story about the novelist "Bret Easton Ellis" and his chilling experiences in the apparently haunted home he shares with his wife and son. In keeping with his usual style, Ellis mixes absurd comedy with a bleak and violent vision. Imperial Bedrooms (2010) follows the characters of Less Than Zero 25 years later; it combines the violence of American Psycho and the postmodernity of Lunar Park with the unaltered ennui of Ellis' debut novel.

Ellis was born to a wealthy California household. His father, who he said was abusive, became the basis of Elis's most well-known character Patrick Bateman, and the frosty relationship between Victor and his father in Glamorama is based in part on this as well. He attended Bennington College, where he met and befriended fellow writers Donna Tartt and Jonathan Lethem, neither of whom were aware of his literary aspirations. After rising to fame with Less Than Zero in 1985, Ellis became closely associated and good friends with fellow Brat Pack writer Jay McInerney: the two became known as the "toxic twins". The writer became a social pariah for a time following American Psycho (1991), which later became a cult hit, moreso after its 2000 movie adaptation; it is now regarded as Ellis' magnum opus and is favorably looked upon by academics. The Informers (1994) was offered to his publisher during Glamorama's long writing history. Ellis wrote a screenplay for The Rules of Attraction's film adaptation which was not used. Ellis records a fictionalized version of his life story up until this point in the first chapter of Lunar Park (2005). After the death of his lover Michael Wade Kaplan, Ellis was spurred to finish Lunar Park and inflected it with a new tone of wistfulness In Lunar Park, through his fictional alter ego and the character's relationship with own son, Ellis resolved some of the issues surrounding his father.

Later, Ellis was approached by young screenwriter Nicholas Jarecki to adapt The Informers into a film; the script they co-wrote was cut from 150 to 94 pages and taken from Jarecki to give to Australian director Gregor Jordan, whose light-on-humor vision of the film was met with unanimously negative reviews when the film was released in 2009. Despite setbacks as a screenwriter, Ellis teamed up with acclaimed director Gus Van Sant in 2009 to adapt the Vanity Fair article "The Golden Suicides" into a film of the same name, depicting the paranoid final days and suicides of celebrity artists Theresa Duncan and Jeremy Blake. In 2010, Ellis released the sequel to his debut novel, in the form of Imperial Bedrooms. Ellis wrote it following his own return to LA and fictionalises his work on the film adaptation of The Informers, from the perspective of Clay. Positive reviews felt it was a culmination of the themes began respectively in Less Than Zero, American Psycho and Lunar Park.

When asked an interview in 2002 whether or not he was gay, Ellis explained that he does not identify himself as gay or straight. He explained that he is comfortable to be thought of as gay, bisexual or heterosexual and that he enjoys playing with his persona, identifying variously as gay, straight and bi to different people over the years.

In his semi-autobiographical novel Lunar Park, the fictional Bret continues both transient affairs and long-term relationships with men and women at various points in the novel. Lunar Park was dedicated to Michael Wade Kaplan and Ellis's father, Robert Ellis, about whom he speaks openly in interviews promoting the novel. Robert Ellis died in 1992. In one interview, Ellis describes feeling a liberation, in the completion of the novel, that allowed him to come to terms with unresolved issues regarding his father. In the "author Q&A" on the Random House website, Ellis comments on his relationship with his father, and says he feels that his father was a "tough case" who left him damaged. Having grown older and having "mellow[ed] out", Ellis describes how his opinion of his father changed since 15 years ago when writing Glamorama (in which the central conspiracy concerns the relationship of a father and son). Even earlier in his career, Ellis based the character of Patrick Bateman from American Psycho on his father.

Less Than Zero was adapted into a film in 1987, directed by Marek Kanievska and starring Andrew McCarthy, Robert Downey Jr and Jami Gertz.

American Psycho was filmed in 2000, directed by Mary Harron and starring Christian Bale, Reese Witherspoon, Chloë Sevigny, Jared Leto and Willem Dafoe.

The Rules of Attraction was filmed in 2002, directed by Roger Avary and starring James Van Der Beek, Shannyn Sossamon and Ian Somerhalder.

A film based on Glamorama was set for a 2007 release, again directed by Avary, but has been delayed for unknown reasons.

Additionally, there is a film called Glitterati made from additional footage that was filmed for The Rules of Attraction.

A film about Ellis, titled This Is Not an Exit: The Fictional World of Bret Easton Ellis, was made in 2000. The film is a combination of a documentary on his life as well as dramatizations of scenes from his books.

An adaptation of the collection of short stories The Informers by Ellis premeried at the Sundance Film Festival in January 2009. Directed by Gregor Jordan, script written by Ellis and Nicholas Jarecki, featuring Mickey Rourke, Kim Basinger, Winona Ryder, Amber Heard, Billy Bob Thornton and the late Brad Renfro.

He recently wrote the screenplay for a film titled The Frog King which is set to start filming with Joseph Gordon-Levitt starring.

His 2005 novel, Lunar Park, is being made into a movie looking towards a 2010 release date. It was adapted into a screenplay by Lane Shadgett.

Ellis often uses recurring characters and settings. Major characters in one novel may become minor ones in the next, or vice versa. Camden College, a fictional New England liberal arts college, is frequently referenced. It is based on Bennington College, which Ellis himself attended, where he met future novelist Jonathan Lethem and befriended fellow writers Donna Tartt and Jill Eisenstadt. In Tartt's The Secret History (1992), her version of Bennington is given as "Hampden College", although there are oblique connections between it and Ellis' Rules of Attraction. Eisenstat and Lethem, however, use 'Bennington' in From Rockaway (1987) and The Fortress of Solitude (2003), respectively. Though his three major settings are Vermont, Los Angeles and New York, he doesn't think of these novels as about these places; they are intentionally more universal than that.

Camden is introduced in Less Than Zero, where it is mentioned that both protagonist Clay and minor character Daniel attend it. In The Rules of Attraction (1987), where Camden is the setting, Clay (referred to as "The Guy from L.A." before being properly introduced) is a minor character who narrates one chapter; ironically, he longs for the Californian beach, where in Ellis' previous novel he had longed to return to college. On "the guy from Clay's door someone wrote "Rest In Peace Called"; R.I.P., or Rip, is Clay's dealer in Less Than Zero; Clay also says that Blair from Less than Zero sent him a letter saying she thinks Rip was murdered. Main character Sean Bateman's older brother Patrick narrates one chapter of the novel; he will be the infamous central character of Ellis' next novel, American Psycho. Ellis includes a reference to Tartt's forthcoming Secret History in the form of a passing mention of "that weird Classics group... probably roaming the countryside sacrificing farmers and performing pagan rituals". There is also an allusion to the main character from Eidenstadt's From Rockaway.

In American Psycho (1991), Patrick's brother Sean appears briefly. Paul Denton and Victor Johnson from The Rules of Attraction are both mentioned; on seeing Paul, Patrick wonders if "maybe he was on that cruise a long time ago, one night last March. If that's the case, I'm thinking, I should get his telephone number or, better yet, his address." Camden is referred to as both Sean's college and the college a minor character named Vanden is going to. Vanden was referred to (but never appeared) in both Less Than Zero and The Rules of Attraction. Passages from "Less Than Zero" reappear, almost verbatim, here, with Patrick replacing Clay as narrator. Patrick also makes repeated references to Jami Gertz, the actress who portrays Blair in the 1987 film adaptation of Less Than Zero. Allison Poole from Jay McInerney's 1988 novel Story of My Life appears as a torture victim of Patrick's. 1994's The Informers features a much-younger Timothy Price, one of Patrick's co-workers in American Psycho, who narrates one chapter. One of the central characters, Graham, buys concert tickets from Less Than Zero's Julian, and his sister Susan goes on to say that Julian sells heroin and is a male prostitute (as shown in LTZ). Alana and Blair from LTZ are also friends of Susan's. Letters to Sean Bateman to a Camden College girl named Anne visiting grandparents in LA comprise the eighth chapter.

Patrick Bateman appears briefly in Glamorama (1998); Glamorama's main characters Victor Ward and Lauren Hynde who were first introduced in The Rules of Attraction. Bateman (portrayed by Christian Bale in the then-in-production 2000 film adaptation) is featured alongside two identical characters: Bale himself, and a spy who is "identical" to Bale. Jamie Fields, who has a major role in the book, was first briefly mentioned by Victor in The Rules of Attraction. Bertrand, Sean and Mitchell, all from The Rules of Attraction, appear in a Camden flashbacks and several other Rules characters are referenced. McInerney's Alison Poole makes her second appearance in an Ellis novel as Victor's mistress. Lunar Park (2005) is not set in the same "universe" as Ellis' other novels, but contains a similar multitude of references and allusions. All the author's previous works are heavily referenced, in keeping with the book-within-a-book structure. Jay McInerney cameos. Donald Kimball from American Psycho questions Ellis on a series of American Psycho-inspired murders, Mitchell Allen from Rules lives next door to and went to college with Ellis (Ellis even recalls his affair with Paul Denton, alluded to in Rules), and Ellis recalls a tempestuous relationship with Blair from LTZ. Although Imperial Bedrooms (2010) establishes the conceit that the Clay depicted in LTZ is not the same Clay who narrates Bedrooms (LTZ being, in Bedrooms, the close-to-non-fiction work of an author friend of Clay's), he is nevertheless the same character. The LTZ film adaptation (featuring actors James Spader, Jami Gertz and Robert Downey, Jr.) exists within the world of the novel, too.

On Bloc Party's 2007 album A Weekend in the City, the opening track, "Song for Clay (Disappear Here)", is based on the main character from Ellis's novel Less Than Zero. The parenthesised part of the title refers to the billboard that Clay drives past in the book.

An album by Porcupine Tree, Fear of a Blank Planet, was largely inspired by Ellis' novel, Lunar Park. While the novel is told from the father's point of view, the record is mostly from the son's point of view, although "My Ashes" reflects the regrets of the son's dead grandfather as they scatter his ashes, referencing the scene at the end of Lunar Park.

Eminem's group D12 have two songs called "American Psycho" and "American Psycho 2".

The Misfits have a song called American Psycho off their 1997 album American Psycho. The song is written about Patrick Bateman and references the story many times.

Bret Easton Ellis is mentioned in the songs "Obsessions" by the UK band Suede and "The Booklovers" by the Northern Irish band The Divine Comedy (which also could be a reference to Ellis phrase "This is not an exit" (American Psycho) taken from Dante's Divine Comedy, Hell - canto III.

A character in Tao Lin's 2009 novella Shoplifting from American Apparel, is said to be reading "a Bret Easton Ellis novel" while on a bus to Atlantic City.

Welsh rock band Manic Street Preachers wrote a song about the character Patrick Bateman entitled "Patrick Bateman". The song was featured on the B-side of their single La Tristesse Durera released July 26, 1993.

In The Simpsons episode "Brother Can You Spare Two Dimes" Uncle Herb gives "The Great Books of Western Civilization" to Lisa as a present. She would receive Ethan Frome first and the rest through installments, ending in Less Than Zero.

The mixed martial arts fighter Stephan Bonnar is nicknamed the "American Psycho" due to his clean cut facial features and resemblance to Patrick Bateman.

The 2009 Australia film The Beautiful and Damned directed by Richard Wolstencroft, and based on the famous sophomore novel by F. Scott Fitzgerald, is dedicated to Ellis.

Portuguese metal band Moonspell named a track in their 1999 album The Butterfly Effect "Disappear Here", having its lyrics inspired by the novel Less Than Zero.

In the 2009 film "17 Again" towards the end of the movie when the lead character, Mike O'Donnell, is describing his wife when he first met her he says when he first saw her she was reading Less Than Zero.

In the 2010 video game "Alan Wake", you play as titular character Alan Wake, deeply enshrouded in the mystery of his missing wife. Through-out the course of the game, Agent Nightengale keeps referring to Alan Wake as other well known horror and mystery writers as a way of antagonizing him. At one, while locked in jail, he refers to him directly as Bret Easton Ellis.