Condon was born in New York City on October 22, 1955, the son of a police detective, and was raised in an Irish Catholic family. He attended Regis High School and Columbia College of Columbia University, graduating in 1976 with a degree in philosophy.
At the age of twelve, Condon found himself drawn to screenplay writing with his first viewing of Bonnie and Clyde:
Part of the pleasure of it was a completely instinctual thing that drew me into the world of writing about movies. Suddenly it became all of your senses—your mind was engaged by it. The most pleasurable thing was that you felt as if you were part of the movement and part of that fun.
In college he saw Sweet Charity (1969) starring Shirley MacLaine. He later described its impact:
Sweet Charity was probably the first movie musical I saw on the screen … It was Bob Fosse’s first movie, and the sense of wonder of somebody that gifted discovering a new medium is just intoxicating.… For me, Sweet Charity started a lifelong love affair with movies that are reviled and rejected in their time, which it was.
After completing college, Condon worked as a journalist for film magazines, including American Film and Millimeter. Circa 1981, he won "the world's most difficult film trivia quiz" sponsored by the Village Voice.
His career as a filmmaker began with screenplays for the independent feature Strange Behavior (1981), an homage to the pulp horror films of the 1950s, and the science-fiction feature Strange Invaders (1983), which starred Nancy Allen and Wallace Shawn. It depicted present-day encounters with extraterrestrials who have been living in Illinois since 1958, when they entered into a secret pact with the Eisenhower administration. His directorial debut was Sister, Sister (1987), an eerie Southern Gothic mystery starring Eric Stoltz and Jennifer Jason Leigh. Test screenings led to major changes to the film, which still proved a critical failure that set back Condon's career.
Condon emerged a few years later directing a series of made-for-TV thrillers, including Murder 101 (1991), which starred Pierce Brosnan and earned Condon and co-writer Roy Johansen a 1992 Edgar Award for their screenplay. During this period he also wrote the screenplay for the thriller F/X2 (1991), which was directed by Australian director Richard Franklin.
In 1994, he directed the television movie The Man Who Wouldn't Die, which starred Roger Moore and Nancy Allen. ABC chose it to air during sweeps week, but reviews were mixed. He directed Candyman: Farewell to the Flesh (1995), a sequel to Bernard Rose's 1992 horror film. It was a critical and commercial failure. Reminded years later of this phase of his career, Condon said: "It's hard to be lower on the totem pole than being the director for a sequel to a horror movie."
Condon wrote and directed Gods and Monsters (1998). He based his screenplay on a novel by Christopher Bram. His screenplay won the Academy Award for Best Adapted Screenplay. The New York Times said Condon "may have been the most stunned person at the Academy Awards when his name was announced as the winner for the best adapted screenplay. He has struggled for years in Hollywood as a screenwriter and journalist and is unaccustomed to the hoopla that is now around him." He was nominated for the same award for his screenplay for Chicago, based on the Broadway musical of the same name. He received a second Edgar Award for his Chicago screenplay as well.
In 2004 he wrote and directed the film Kinsey, chronicling the life of the controversial sex researcher Alfred Kinsey. In the New York Times, A.O. Scott wrote that "Bill Condon's smart, stirring [film] has a lot to say on the subject of sex, which it treats with sobriety, sensitivity and a welcome measure of humor." He continued: "I can't think of another movie that has dealt with sex so knowledgeably and, at the same time, made the pursuit of knowledge seem so sexy. There are some explicit images and provocative scenes, but it is your intellect that is most likely to be aroused.... Mr. Condon's great achievement is to turn Kinsey's complicated and controversial career into a grand intellectual drama."
In 2005, he received the Stephen F. Kolzak Award at the GLAAD Media Awards.
Condon wrote the screenplay for and directed Dreamgirls, an adaptation of the acclaimed Broadway musical of the same name based on the career of the musical group The Supremes. It was released in December 2006. Condon received Directors Guild of America and Broadcast Film Critics Association nominations for directing. The film was nominated in eight Academy Awards in six categories, but not for best film, directing, or screenplay.
Condon was executive producer of the 81st Academy Awards television broadcast that aired on February 22, 2009, Oscars telecast, working with producer Laurence Mark.
Condon directed both parts of The Twilight Saga: Breaking Dawn (2011 and 2012) adapted from the fourth and final novel in The Twilight Saga by Stephenie Meyer. He was twice nominated for a Razzie for Worst Director for these films, winning for Part 2.
Condon directed The Fifth Estate (2013), a thriller about Wikileaks starring Benedict Cumberbatch. He said he chose the project for a change of pace and liked its non-ideological approach to a very complex subject. He saw it "in the great tradition of journalistic thrillers". It failed with critics and at the box office. Condon said he was shocked by the complete lack of public interest and questioned the public appeal of its principal subject, Julian Assange. He said: "I do think there's something about him that does not suggest an evening's entertainment."
In late 2013, he directed a revised version of the 1997 stage musical Side Show at the La Jolla Playhouse. A production of this revision played in June and July 2014 at the Kennedy Center. Charles Isherwood described it in the New York Times as "a full-scale reimagining" of the musical that involved "the addition and subtraction of several songs ..., the reordering of others", and new dialogue contributed by Condon. That production received excellent reviews when it moved to Broadway in the fall, but it proved a failure at the box office and closed after just seven weeks.
In 2015, Condon directed Mr. Holmes starring Ian McKellen. Condon noted its similarity to Gods and Monsters, not only because of its lead actor but because "Both movies are about aging and mortality. You have a celebrated man facing the decline of his public image."
Condon directed a live-action film adaptation of the animated 1991 film Beauty and the Beast. A few weeks before the film's scheduled release on March 17, 2017, Condon announced that one character has "a nice, exclusively gay moment", which resulted in an "internet meltdown" of contrasting support and condemnation.
He is credited as co-author of the screenplay for The Greatest Showman, a life of P.T. Barnum starring Hugh Jackman, scheduled for release in December 2017. He rewrote the draft of co-author Jenny Bicks.
Condon is set to direct a remake of Bride of Frankenstein for Universal Pictures starring Javier Bardem as Frankenstein's Monster, scheduled for release February 14, 2019.
Condon is a member of the Independent Feature Projects (IFP) in Los Angeles, a non-profit organization which supports independent films, as well as the Independent Writers Steering Committee, which was initiated by the Writers Guild of America (WGA).
Condon is openly gay. He is in a long-term relationship with Jack Morrissey.