Adair was born in Edinburgh but from 1968 to 1980 he lived in Paris. His early works of fiction included Alice Through the Needle’s Eye (following Alice’s Adventures in Wonderland and Through the Looking-Glass) and Peter Pan and the Only Children (following Peter and Wendy). He won the Author’s Club First Novel Award in 1988 for his novel The Holy Innocents. From 1992 to 1996 he wrote the “Scrutiny” column for The Sunday Times. During 1998 and 1999 he was the chief film critic of The Independent on Sunday, where in 1999 he also wrote a year-long column called “The Guillotine”.

The film Love and Death on Long Island (1997), directed by Richard Kwietniowski, was based on his 1990 novel of the same name. The film The Dreamers (2003) directed by Bernardo Bertolucci, with a script by Adair, was based on his book The Holy Innocents, which Adair revised and re-released under the same title as the film. Adair collaborated on the screenplays of several Raúl Ruiz films: The Territory (1981), Klimt (2006) and A Closed Book (2010).

In 1995 he won the Scott Moncrieff Translation Prize for his book A Void, which is a translation of the French book La Disparition by Georges Perec. The original book contains no instances of the letter e; Adair translated it with the same limitation. His works are compared to those of Julian Barnes, A. S. Byatt and Patrick Gale. His book Flickers: A History of the Cinema in 100 Images was admired by David Foster Wallace.

Adair himself was homosexual, though he rarely talked about the matter, not wishing to be labelled. “Obviously there are gay themes in a lot of my novels,” he said in a recent interview, “but I really wouldn’t be happy to be thought of as a ‘Gay Writer’ … Being gay hasn’t defined my life.” At the end of his life, he lived in London. Adair died from a brain haemorrhage, 13 months after suffering a stroke which blinded him on 8 December 2011, twenty-one days away from his 67th birthday. He was writing a stage version of Love and Death on Long Island, which is being developed by producers New Gods and Heroes, at the time of his death.