[5] When he was three, Barker witnessed the French skydiver Léo Valentin plummet to his death in 1956 during a performance at an air show in Liverpool.

[8] He co-founded the avant-garde theatrical troupe The Dog Company in 1978 with former school friends and up and coming actors, many of whom would go on to become key collaborators in Barker's film work.

[9] Over the next five years Barker wrote nine plays, often serving as director, including some of his best-known stage productions, The History of The Devil, Frankenstein in Love, and The Secret Life of Cartoons.

He began writing horror early in his career, mostly in the form of short stories (collected in Books of Blood 1–6) and the Faustian novel The Damnation Game (1985).

[14] In early 2024, he announced he would stop attending conventions and public events so he could focus more on his writing, as he was working on the manuscripts for 31 different projects, some closer to completion than others.

[20] Barker said in a December 2008 online interview (published in March 2009) that he had throat polyps which were so severe, a doctor told him he was taking in only 10% of the air he was supposed to.

[22] Realising he might have just a short time to live, he decided to put his personal concerns about the world and society into the upcoming novel Deep Hill, which he thought could be his final book.

[24] While appearing on the radio call-in show Loveline on 20 August 1996, Barker said that in his teens he had several relationships with older women, but came to identify himself as homosexual by 18 or 19.

He had been working on a series of film adaptations of his The Abarat Quintet books under The Walt Disney Company's management,[26] but due to creative differences, the project was cancelled.

[27] He served as an executive producer for the 1998 film Gods and Monsters,[28][29] a semi-fictional tale of Frankenstein director James Whale's later years, which won an Academy Award for Best Adapted Screenplay.

In 2020, Barker regained control of the Hellraiser franchise, and served as executive producer on a 2022 reboot film for the streaming service Hulu.

[35] Barker was involved in a streaming service film adaptation of The Books of Blood in 2020,[36] and is developing a Nightbreed television series directed by Michael Dougherty and written by Josh Stolberg for SyFy.

Verheiden, Dougherty and Green will also be executive producing the series with Danny McBride, Jody Hill, Brandon James and Roy Lee of Vertigo Entertainment.

In 2005, IDW published a three-issue adaptation of Barker's children's fantasy novel The Thief of Always, written and painted by Kris Oprisko and Gabriel Hernandez.

In December 2007, Chris Ryall and Clive Barker announced an upcoming collaboration of an original comic book series, Torakator, to be published by IDW.