Malcolm McDowell is an actor that is often cast as a villain, but for Phineas and Ferb, he provides the voice of Grandpa Reginald Fletcher. He is the only actor so far to play both King Arthur and Merlin. In Star Trek Generations, his character of Dr. Tolian Soran was a nemesis to James Kirk, which is the same kind of role that Khan Noonien Singh had in an earlier Star Trek episode and movie. Singh was played by Ricardo Montalbán, and both Ricardo and Malcolm have both played the role of Mr. Roarke on Fantasy Island.
- Alex, A Clockwork Orange
- Albert Schweitzer, Light in the Jungle: The Story of Dr. Albert Schweitzer
- Dr. Tolian Soran, Star Trek Generations
- Geoffrey Tolwyn, Wing Commander Academy and the third and fourth Wing Commander video games
- Mr. Roarke, Fantasy Island (1998)
- John Corben/Metallo, Superman: The Animated Series
- Daniel Linderman, Heroes
- Reginald Fletcher, Phineas and Ferb
- Father of actress Lilly McDowell and producer/director Charlie McDowell.
- First well-known actor to appear non-animated and in the flesh for South Park.
- Not related to, but shares more than just a last name with, Roddy McDowell: Roddy McDowell played several roles on the first Fantasy Island series. One of those roles was Mephistopheles (a devil). Malcolm McDowell's version of Mr. Roarke on the second Fantasy Island series was much darker than Ricardo Montalbán's version.