Jacobi also made two dozen feature films. His film debut was in the 1953 British comedy, "Is Your Honeymoon Really Necessary?" with the country’s blond sex symbol of the day, Diana Dors. Other notable films in which he appeared include, "The Diary of Anne Frank" (1959), "Irma la Douce" (1963), "Penelope" (1966), "Everything You Always Wanted to Know About Sex* (*But Were Afraid to Ask)" (1972) as Sam Musgrave, a middle-aged married man experimenting with women's clothes, "Arthur" (1981) as the lucky florist, "My Favorite Year" (1982) as Benjy's unsophisticated Uncle Morty, and in "Amazon Women on the Moon" (1987), as a man named Murray who got zapped into the television and is wandering throughout sketches looking for his wife. In Barry Levinson’s "Avalon" (1990), in a semi-dramatic role, as one of four Russian brothers (elders) trying to build a future in Baltimore in the early 20th century, with the memorable comic relief catchphrase, "You cut the 'toikey' without me!?" after he would notoriously arrive late to family Thanksgiving dinner, every year. His final film role was "I.Q." (1994), playing philosopher/mathematician Kurt Gödel.