Denholm entered RADA at the age of 17, but dropped out after a year having hated every minute being there. He joined the RAF in 1940, trained as a gunner/radio operator, and was shot down over Germany in 1942. In the POW camp he and his fellow prisoners staged various productions in a theatre constructed out of old packing cases. After the war he joined a London repertory company and his career took off particularly when Laurence Olivier chose him for the starring role in Venus Observed, for which he won a Clarence Derwent award. When another Olivier production Ring Around the Moon transferred to New York Denholm replaced Paul Schofield in what became a Broadway hit. Returning to Britain he was signed to a film contract and appeared in such movies as The Cruel Sea, The Sound Barrier, Alfie, King Rat, and others in addition to appearing on television and making countrywide theatre tours. In 1983 he won a BAFTA Award for his role as the butler in Trading Places and followed it with a Best Supporting Actor Award for his role in A Private Function. Prior to that he won an Evening Standard Best Actor award for Bad Timing.