Paul began his career in Los Angeles after serving in the European Front during World War II. His television cameo appearances in the 1950's included Alfred Hitchcock Presents, Dragnet, Sea Hunt, and Playhouse 90.
He moved to England and married a Scottish woman he met during the war. His career blossomed with feature roles in The Saint and movies such as The Haunting - 1963 co-staring Julie Christie; It ! - 1966 co-staring Anthony Perkins; The Pink Panther Strikes Again; A Bridge Too Far; Rustlers' Rhapsody - 1985 co-staring Tom Berringer and Sela Ward; Aliens; and Indiana Jones and the Last Crusade. He aslo held the role of the American officer Steve Tanner who married Elsie Tanner in the long-standing British soap opera Coronation Street.