Fox's career showed great promise with his role as a boy whose life gets complicated once he acquires "The Magnet" (1951), but he soon gave up acting to finish school. He did not return to acting until a decade later, but quickly enjoyed success in the role of a haughty but ultimately malleable aristocrat strangely corrupted by his butler (Dirk Bogarde) in Joseph Losey's striking drama, "The Servant" (1963). This part, one of Fox's finest, typified many of his subsequent roles: classy yet often duplicitous, prone to weakness, decadence, and bad judgment.
Successfully venturing to Hollywood, Fox essayed similar characterizations in "King Rat" (1965), as a POW under the influence of a schemer (George Segal), and in "The Chase" (1966), as Jane Fonda's wealthy but spineless Texas husband. More conventional leading man duties came with "Thoroughly Modern Millie" (1967) and as one of the lovers of "Isadora" (1968) in that biopic of the dancing Duncan. Perhaps Fox's finest work in this period came in the bizarre but galvanizing "Performance" (1970), as a vicious hit man on the lam who hides out at a reclusive rock star's (Mick Jagger) mansion and falls prey to a series of bisexual orgies and weird costume changes.
Fox left acting in 1973 when he joined a Christian missionary group, the Navigators, though he did act in the story of a suicidal woman saved by religion, "No Longer Alone" (1978). Since his return to acting in the early 80s, Fox has been more prolific than ever, alternating offbeat, small-scale efforts ("Pavlova" 1983, "As You Like It" 1992), with mainstream Hollywood fare ("The Russia House" 1990, "Patriot Games" 1992) and prestigious historical epics. With his distinguished middle-aged bearing, Fox has usually incarnated a series of old guard authority figures: David Lean specifically asked for him for "A Passage to India" (1984), and Fox was also effective as a British statesman who misguidedly gives in to his own prejudices and weaknesses while placating the Nazis in the name of peace in "The Remains of the Day" (1993). He is the son of influential talent agent Robin Fox, and brother of actor Edward and theatrical producer Robert.