He was born Derek Jules Gaspard Ulric Niven Van Den Bogaerde, in Hampstead, north London, on 28 March 1921, the son of a half-Dutch father, then picture editor of the Times, and an actress mother.
Educated at University College School in London, he was sent as a teen to live with Scottish relatives. An art school drop-out and unpromising drama student, he served during the Second World War with the Air Photographic Intelligence Unit and later admitted that the misery he witnessed during the war - in particular, a visit to Belsen the day after it was liberated - greatly influenced his later outlook on life.
A year out of uniform, his life changed dramatically: he began an acting career that saw him rapidly transformed into a matinee idol of the 1950s, one of the most popular and respected performers on both sides of the Atlantic.
During his prodigious career he made 70 feature films, ranging from the Doctor in the House series to classics like Death in Venice (1971).
Sir Dirk also played key roles in a wide spectrum of films, including the role of Dr Simon Sparrow in several of Richard Gordon's Doctor in the House medical comedies, the romantic role of Sidney Carton in A Tale of Two Cities (1958), King and Country (1965), and A Bridge Too Far. He won British Academy Awards for best actor in The Servant and Darling and occasionally appeared in stage plays, including Power Without Glory.
Later, as he entered his fifties, he enjoyed a second career as a novelist, with successful books including A Gentle Occupation, Voices in the Garden, West of Sunset, Jericho and A Period of Adjustment.
He also wrote several autobiographical books, including A Postillion Struck by Lightning, Snakes and Ladders and For The Time Being, published last year. He described them as "a six-volume ego trip" - a re-sifting of 78 years of a what was, at times, a very private life.
He was knighted in 1992. But although he was often in the public gaze, even during a 20-year spell in the south of France, friends said he was always happiest in his own company. In Backcloth, the fourth volume of his autobiography, he called himself a "hermit crab" and described his dread of "possession".
Although he documented with frankness his early sexual encounters with girls and later his adoring love for Kay Kendall and Judy Garland, he never wrote about his longest and closest relationship - with his friend and manager for more than 50 years, Tony Forwood.
Sir Dirk said the clues to his private life were in his books. "If you've got your wits about you, you will know who I am."
A place in history was not one of his priorities. He said, with customary self-deprecation: "I don't care if I am remembered or not. It doesn't matter on your gravestone, does it? I have said that in my will: no funeral, no memorial service ... just forget me."