[1] Haig was born on 20 September 1955 in Aldershot, Hampshire,[2] the son of opera singer Shirley R. C. (née Brooks) and army officer (and later director of the Hayward Gallery) Francis W. He had a younger sister who died at 22 of a brain aneurysm when he was 26.
Haig wrote the play My Boy Jack,[2] and later appeared as Rudyard Kipling, alongside Daniel Radcliffe, in television adaptation.
[2] In January 2013, Haig started appearing as Jim Hacker in a re-make of classic 1980s comedy series Yes Prime Minister, broadcast on Gold TV in the United Kingdom.
[4] Filming for a full six-part series of the sitcom, The Wright Way (formerly known as Slings and Arrows) was completed in March 2013, and began airing on BBC One on 23 April.
[5] An August 2018 announcement indicated that Haig would be among the new cast to join the original actors in the Downton Abbey film which started principal photography at about the same time.
Haig has appeared in several stage productions in London's West End, including Hitchcock Blonde at the Royal Court, Life X 3 at the Savoy Theatre, as the character Osborne in R.C.
In 2010 he played the role of Jim Hacker in the stage version of Yes, Prime Minister,[9] at the Chichester Festival Gielgud Theatre, in London's West End from 17 September 2010.
[10] In September 2023, it was announced that Haig was adapting Philip K. Dick's novella "The Minority Report" for the stage, to premiere at the Lyric Hammersmith the following spring.