Irvine Welsh was born in Edinburgh in 1958. He lived in London after leaving school, but returned to his native city where he worked in the Council's housing department. He gained a degree in computer science and studied for an MBA at Heriot Watt University.

His first novel, Trainspotting (1993), a blackly comic portrait of a group of young heroin users living in Edinburgh in the 1980s, was adapted as a film directed by Danny Boyle, starring Ewan McGregor and Robert Carlyle, in 1996. The Acid House, a collection of short stories, was published in 1994 and was followed by Welsh's second novel, Marabou Stork Nightmares (1995), a harrowing stream-of-consciousness narrated by football hooligan Roy Strang. Ecstasy: Three Tales of Chemical Romance, a collection of three novellas, was published in 1996, and a third novel, Filth, a vivid account of the violent adventures of a bigoted, racist and corrupt Scottish policeman, was published in 1998. Glue (2001), is the story of four boys growing up in an Edinburgh housing estate. Porno, a sequel to Trainspotting, was published in 2002.

Welsh is also the author of the plays, Headstate (1994) and You'll Have Had Your Hole (1998). 4 Play, an omnibus edition of four stage adaptations of Welsh's fiction by Harry Gibson and Keith Wyatt, was published in 2001. His screenplay of The Acid House was directed for Channel 4 Films by Paul McGuigan (1998).

His journalism includes a column for Loaded magazine and occasional articles for The Guardian. He is also a DJ and has recorded a single with rock group Primal Scream. In February 2003 Irvine Welsh began writing a Monday column for the Daily Telegraph.