| Year | Title | Role | Notes | Ref |
| 1960 | The Pusher | Detective | | |
| 1961 | West Side Story | Glad Hand, Social Worker Leading Dance | American romantic musical drama film directed by Robert Wise and Jerome Robbins. The film is an adaptation of the 1957 Broadway musical of the same name, which in turn was inspired by William Shakespeare's play Romeo and Juliet. | |
| 1962 | That Touch of Mink | Mr. Everett Beasley | | |
| 1963 | Move Over, Darling | Clyde Prokey | The picture was a remake of a screwball comedy film, My Favorite Wife (1940), with Irene Dunne, Cary Grant and Gail Patrick. In between these movies, a version entitled Something's Got to Give began shooting in 1962, directed by George Cukor and starring Marilyn Monroe and Dean Martin, but was never finished. | |
| The Wheeler Dealers | SEC official | Released as Separate Beds in the UK | |
| 1967 | The Spirit Is Willing | Dr. Frieden | | |
| 1968 | Candy | Daddy / Uncle Jack | Sex farce film directed by Christian Marquand based on the 1958 novel by Terry Southern and Mason Hoffenberg, from a screenplay by Buck Henry. The film satirizes pornographic stories through the adventures of its naive heroine, Candy, played by Ewa Aulin. | |
| 1969 | Viva Max! | Sergeant Valdez | Comedy film | |
| 1971 | Bunny O'Hare | Ad | American comedy film directed by Gerd Oswald. Bette Davis was unhappy with the final film and sued AIP for $3.3 million in damages. | |
| 1972 | Un secuestro de locura | Star | Spanish-language film. Directed by Cy Howard. | |
| Evil Roy Slade | Evil Roy Slade | | |
| Get to Know Your Rabbit | Mr. Turnbull | | |
| Every Little Crook and Nanny | Vito Garbugli | | |
| Wacky Taxi | Pepper | | |
| 1973 | The Brothers O'Toole | Michael O'Toole / Desperate Ambrose Littleberry | American comedy western film directed by Richard Erdman. Michael O'Toole, a roguish gambler and con artist, and younger brother Timothy O'Toole, a womanizer, turn the sleepy mining town of Molybdenum, Colorado upside down. | |
| 1976 | Freaky Friday | Bill Andrews | American fantasy comedy film directed by Gary Nelson. | |
| 1985 | National Lampoon's European Vacation | Kent Winkdale (host of "Pig in a Poke") | Originally given the working title Vacation '2' Europe. The second film in National Lampoon's Vacation film series. | |
| 1987 | Teen Wolf Too | Dean Dunn | American comedy film The sequel to Teen Wolf. | |
| Body Slam | Scotty the car dealer | American comedy film directed by Hal Needham. | |
| 1988 | Return of the Killer Tomatoes | Professor Mortimer Gangreen | A horror comedy film The second film in the Attack of the Killer Tomatoes film series. | |
| 1989 | Night Life | Uncle Verlin | A horror comedy film | |
| 1990 | Gremlins 2: The New Batch | Janitor | | |
| Killer Tomatoes Strike Back | Professor Mortimer Gangreen | The third film in the Attack of the Killer Tomatoes film series. | |
| 1991 | Killer Tomatoes Eat France | Professor Mortimer Gangreen | The fourth film in the Attack of the Killer Tomatoes film series. | |
| 1993 | Stepmonster | Minister | Direct-to-video film | |
| 1994 | The Silence of the Hams | The Ranger | Italian: Il Silenzio dei Prosciutti Parody film of many popular thriller and horror films, notably The Silence of the Lambs and Psycho. | |
| Huck and the King of Hearts | Zach | | |
| 1996 | The Frighteners | The Judge | New Zealand-American horror comedy fantasy film directed by Peter Jackson and co-written with Fran Walsh. | |
| 2001 | Betaville | President Sender | | |
| 2006 | What the Bleep!?: Down the Rabbit Hole | Dr. Quantum | Voice | |
| 2015 | Starship II: Rendezvous with Ramses | Professor Peabody | | |
| 2025 | Attack of the Killer Tomatoes: Organic Intelligence | Professor Mortimer Gangreen | The fifth film in the Attack of the Killer Tomatoes film series. | |
