He was the only actor to appear in three consecutive Stanley Kubrick films. First, he played the central character Alex's "P" (as in "M" and "P" for "Ma" and "Pa") in A Clockwork Orange (1971). Subsequently, he played Graham, the Lyndon family Lawyer, in Barry Lyndon (1975), and Delbert Grady, the original caretaker who murdered his family in The Shining (1980). Stone was discovered when Kubrick saw him perform in David Storey's stage play, The Contractor. The only other actor to be credited in three Kubrick films is Joe Turkel.
Other film roles included parts in Thunderball, Where Eagles Dare, Quest for Love, Flash Gordon and Indiana Jones and the Temple of Doom. In the 1978 Ralph Bakshi's animated film The Lord of the Rings, he voiced the role of Théoden.
Stone was married to Margaret Pickard until her death, in 1984.
