Peter Davison (born Peter Malcolm Gordon Moffett) was born Peter Moffett in Streatham, London, son of an electrical engineer who was originally from Guyana. Before becoming an actor, he attended Winston Churchill School, St John's, Woking, Surrey. He studied at the Central School of Speech and Drama. His first job was as an actor and assistant stage manager at the Nottingham Playhouse.

His first television work was in a 1975 episode of the children's science fiction television programme The Tomorrow People, alongside American actress Sandra Dickinson, whom he married on 26 December 1978. The couple composed and performed the theme tune to Button Moon, a children's programme broadcast in the 1980s. In 1977, Davison appeared in the TV miniseries Love for Lydia opposite Jeremy Irons.

In 1978, Davison's performance as as Tristan Farnon in the BBC adaptation of James Herriot�s All Creatures Great and Small made him a household name. Davison appeared in some British sitcoms, including Holding the Fort, Sink or Swim and Ain't Misbehavin', as well as appearing in dramatic roles.

In 1981, Davison was cast as the Fifth Doctor by producer John Nathan Turner. At age 29, he was at the time the youngest actor to have played the lead role. He stayed with the series for three years seeing it through a period when it lost its traditional Saturday evening slot and was shown twice weekly in the early evening. He returned to the role in the 1993 multi-doctor charity special Dimensions in Time and in the 1997 video game Destiny of the Doctors and once more in "Time Crash", a special episode written by Steven Moffat for Children in Need. He continues to reprise the role in a series of audio plays by Big Finish Productions.

Following his time in the series Davison played Dr Stephen Daker, the hero of A Very Peculiar Practice, written by Andrew Davies, and played the lead in Campion, a series based on the period whodunnits of Margery Allingham.

Davison has appeared in several radio series including Change at Oglethorpe in 1995 and Minor Adjustment in 1996. In 1985 he appeared in the BBC Radio 4 comedy drama series King Street Junior, as teacher Eric Brown. In 1994, he provided the voice of Mole in the animated special of The Wind in the Willows Mole's Christmas.

Davison has had a considerable stage career. In 1984, he appeared in Neil Simon's Barefoot in the Park at the Apollo Theatre and in 1991, in Arsenic and Old Lace at the Chichester Festival Theatre. Other theatre appearances include: The Last Yankee, by Arthur Miller at the Young Vic Theatre and later the Duke of York's Theatre, London in 1993, and Vatelin in An Absolute Turkey, by Georges Feydeau, at the Gielgud Theatre in 1994. In 1996 he played the role of Tony Wendice in the theatrical production of Dial M for Murder. He appeared as Amos Hart in Chicago at the Adelphi Theatre in 1999, and as Dr Jean-Pierre Moulineaux, in Under the Doctor at the Churchill Theatre, Bromley and later at the Comedy Theatre, London in 2001. Davison performed as King Arthur in the London production of Spamalot and as Professor Callahan in the West End production of Legally Blonde, which opened at the Savoy Theatre.

In November 2010 it was announced that Davison would be joining the regular cast of the UK version of Law and Order as Henry Sharpe, the Director of the CPS.