Moray Watson's father was killed in Belgium in World War II. He was educated at Eton College. He met his Future wife Pam Marmont at The Webber Douglas Academy of Dramatic Art. They went on to marry in 1955 and had two children Emma in 1957 and Robin in 1959, both of whom went into the theatre. His father-in-law was the silent film star Percy Marmont.

In 1963, he went to New York City to appear in The Private Ear and The Public Eye. He played the part of the Art Editor in the BBC series Compact for some years.

Watson had a series of television credits to his name, most notably as Brigadier Arthur Maiford, MC (ret.) (but always known to the Larkins as "The General") in The Darling Buds of May (1991–1993); and George Frobisher in Rumpole of the Bailey (1978–1992). He also appeared as Sir Robert Muir in the Doctor Who story Black Orchid; and had a small role in Yes Minister. He also appeared in the 1974 version of The Pallisers as Barrington Erle and in the Albert Campion mystery The Death of a Late Pig as the Chief Constable. He also played a Chief constable in the 1977 BBC series Murder Most English and Mr Bennet in the 1980 BBC series Pride and Prejudice.

In addition to his long career on stage, television and film Moray Watson undertook three one-man shows. The first in the 1970s was The Incomparable Max based on the life and work of Max Beerbohm, written for him by Sheila Ward and Peter Ling. Years later in the early 2000s he took on Ancestral Voices, based on the diaries of James Lees Milne written by Hugh Massingberd. His final one-man show was written and devised by himself based on his own life as an actor, entitled Looking Back and Dropping Names, which was published in book form in September 2016. Watson died at the age of 88 on 2 May 2017.