Born in Wimbledon, South London in 1961, to Daphne and Alec Clunes. A classically trained actor, Alec passed away when Martin was eight.
Martin was married to Lucy Aston between 1990 and 1997. He is currently married to Philippa Braithwaite, with whom he has a daughter, Emily (b. 2000).
Philippa is a television producer, and they work together on Doc Martin.