His stage roles ranged from musical comedy to Shakespeare, and years of such versatile acting on two continents led to many offers to appear in films.

In 1941, Greenstreet began working for Warner Bros. His debut film role was as Kasper Gutman ("The Fat Man") co-starring with Humphrey Bogart in The Maltese Falcon.

He had dramatic roles, such as William Makepeace Thackeray in Devotion (1946), and witty performances in screwball comedies, such as Alexander Yardley in Christmas in Connecticut (1944).

After little more than eight years, Greenstreet's film career ended with Malaya (also 1949), in which he was billed fourth, after Spencer Tracy, James Stewart and Valentina Cortese.

[6] He is interred at Forest Lawn Memorial Park, Glendale, California, in the Utility Columbarium area of the Great Mausoleum, inaccessible to the public.

[citation needed] Living relatives from his sisters (Laura Maude Greenstreet) marriage to Albert Elijah White still reside in the UK today.