He made his television singing debut on Pebble Mill (1972).
On 8 August 2001, in Belsize Park, London, he made a citizen's arrest after a 15-year-old youth allegedly stole a video camera from his car. Davison gave chase and then restrained the youth for 10 minutes before police arrived.
He is the father, with Sandra Dickinson, of actress Georgia Moffett. He is the grandfather to Tyler Peter Moffett (b. May 2002) and Olive Tennant (b. March 2011). He is also the father, with Elizabeth Heery, of sons, Louis Davison and Joel James Davison.
He became the youngest actor to be cast as the Doctor in Doctor Who (1963) in 1981, aged just 29 when he made his first appearance in the role. When he reprised the role of the Doctor in 2007 at the age of 56, he was older than William Hartnell was when Hartnell originated the role at the age of 55. His record as the youngest Doctor was broken in 2009 when 26-year-old Matt Smith was cast for the role in Doctor Who (2005).
He enjoys reading and contributed book reviews for Richard & Judy (2001).
Along with Elisabeth Sladen and John Leeson, he is one of only three actors to play the same character (the Doctor) in both Doctor Who (1963) and Doctor Who (2005).
Of the 20 Doctor Who (1963) stories he starred in, his favorite was his final one, Doctor Who: The Caves of Androzani: Part One (1984), largely due to the combination of Robert Holmes's writing and Graeme Harper's direction. It has also been repeatedly voted one of the best stories ever by fans. He has cited Doctor Who: The Visitation: Part One (1982) and Doctor Who: Earthshock: Part One (1982) as his other favorites.
His favorite roles on television have been A Very Peculiar Practice (1986), At Home with the Braithwaites (2000), Mystery!: Campion (1989) and All Creatures Great and Small (1978).
He has named Martyn Friend, David Tucker and Graeme Harper as his favorite directors.
He has had a regular role in a total of thirteen different television series: All Creatures Great and Small (1978), Holding the Fort (1980), Sink or Swim (1980), Doctor Who (1963), A Very Peculiar Practice (1986), Mystery!: Campion (1989), Fiddlers Three (1991), Ain't Misbehavin (1994), At Home with the Braithwaites (2000), The Last Detective (2003), Distant Shores (2005), The Complete Guide to Parenting (2006), Fear, Stress and Anger (2006) and Law & Order: UK (2009). In most cases, he played the male lead.
He is the father-in-law to David Tennant. Davison was the Fifth Doctor and Tennant was the Tenth. Tennant has always been very open about the fact that Davison was his favorite Doctor and he presented the documentary Come in Number Five (2011), which covered the production of the Davison era of the series and featured as an extra on the Special Edition DVD release of Doctor Who: Resurrection of the Daleks: Part One (1984).
His mother was born in India as her father was a British Army officer serving in Calcutta at the time.
When it was announced in 1980 that Davison was to play the Fifth Doctor, Patrick Troughton, who played the Second Doctor, advised the 29-year-old actor to limit his time on the series to three years, as he had done, in order to avoid being typecast. Davison followed this advice. In March 1987, Davison advised Sylvester McCoy, who had been announced as the Seventh Doctor that month, to do likewise. However, the advice proved academic as the series was canceled in 1989 by Peter Cregeen, the BBC's new Head of Series.
In August 2007, he starred as King Arthur in the musical "Monty Python's Spamalot" at the Palace Theatre in London's West End.
He was offered the role of Roger Derebridge in Lifeforce (1985). It was ultimately played by Nicholas Ball. If Davison had accepted, he would have acted with his future wife, Elizabeth Heery. He was also considered for Col. Colin Caine in the film, played by Peter Firth.
While at the Central School of Speech and Drama, one of Davison's fellow students was Dave Clark from The Dave Clark Five. As a result, Davison made an appearance on Top of the Pops (1964) as part of the crowd singing along to the band when they performed their 1970 number eight hit single "Everybody Get Together".
He acted again with Nicola Bryant (his former co-star in his final episodes of Doctor Who (1963)) in the film Parting Shots (1998), a Michael Winner film which, despite an all-star cast, appeared in a UK poll of Empire magazine readers' "50 Worst Movies Ever".
His role as Tristan Farnon in the hugely popular BBC series All Creatures Great and Small (1978) made him a household name in the UK. It also led directly to his starring role in Doctor Who (1963). He was cast as the Fifth Doctor by producer John Nathan-Turner, who had worked with him when he was the production unit manager on All Creatures Great and Small (1978). Nathan-Turner said he cast Davison as the Doctor because he had "the right combination of light humour, drama and realism, is very popular with children, and has a large following with feminine viewers".
He was the first actor to play the Doctor who had studied at the Central School of Speech and Drama. The second was Christopher Eccleston.
He provided a DVD commentary for every Doctor Who (1963) serial he starred in except Doctor Who: The Awakening: Part One (1984), for which his place was taken by series expert Toby Hadoke.
He closed his Twitter account in July 2017 after receiving a ferocious backlash to "role model" comments that he made in an interview questioning the Doctor in Doctor Who (2005) having a sex change to becoming a woman with the casting of Jodie Whittaker. Even former Labour Party leader Ed Miliband tweeted to criticize Davison's comments as "the views of the 1950s", while actor Phil Davis said (while not specifically mentioning Davison) that anyone who thinks the Doctor shouldn't be a woman is talking "claptrap".