Martin Eugene Mull (born August 18, 1943 in Chicago, Illinois) is an American actor, comedian and singer. He played Colonel Mustard in Clue and has had roles on Mary Hartman, Mary Hartman, Roseanne, Sabrina the Teenage Witch, Danny Phantom, Arrested Development and Two and a Half Men. He was also a regular celebrity during the Tom Bergeron run of The Hollywood Squares and was the center square for its final season.
- Mary Hartman, Mary Hartman (1976-1977): Garth Gimble/Barth Gimble.
- Mr. Mom (1983): Ron Richardson.
- Clue (1985): Colonel Mustard.
- Roseanne (1991-1997): Leon Carp.
- Mrs. Doubtfire (1993): Justin Gregory.
- Jingle All the Way (1996): D.J.
- Sabrina the Teenage Witch (1997-2000): Willard Kraft.
- Danny Phantom (2004-2007): Vlad Plasmius/Vlad Masters.
- Arrested Development (2004-2013): Gene Parmesan.
- American Dad! (2005-2011): Father Donovan.
- Two and a Half Men (2008-2013): Russell.
- dads (2013-2014): Crawford Whittemore.