Television:
* SCTV (1976-1984) - Played a variety of characters, including the iconic "King Tut" and "The Great White North" segments.
* Saturday Night Live (1975-1976) - He was a writer and performer during the show's first season.
* The Kids in the Hall (1989-1995) - Recurring guest star.
* The Larry Sanders Show (1992-1998) - Recurring character as "Marty Funkhouser".
* Frasier (1993-2004) - Guest star in several episodes as "Mel" the crabby, loud, and often insulting neighbor.
* The Simpsons (1989-present) - Voiced various characters including "Dr. Marvin Monroe".
* King of the Hill (1997-2009) - Voiced "Hank Hill's" co-worker "Boomhauer".
* Aqua Teen Hunger Force (2000-2015) - Voiced "Carl" in the episode "The Ballad of Carl".
* The Critic (1994-1995) - Voiced "Floyd" in the episode "Death of a Critic".
* The Venture Bros. (2003-2018) - Voiced "Dr. Thaddeus Venture Sr." in the episode "The Project (Part 2)".
* Trailer Park Boys (2001-2007) - Guest star in the episode "The Big Dirty".
Movies:
* The Kentucky Fried Movie (1977) - Played "The Devil" and "The Old Man"
* History of the World, Part I (1981) - Played "The Roman Guard" and "The Innkeeper"
* Meatballs (1979) - Played "The Counselor"
* One Crazy Summer (1986) - Played "Dr. Stein"
* The Super Mario Bros. Super Show! (1989) - Played "King Koopa"
* The Wrong Guys (1988) - Played "The Mayor"
* A Mighty Wind (2003) - Played "Mitch"
* The Last Winter (2006) - Played "Father Martin"
This is not an exhaustive list, but it includes some of his most notable roles. He has also had roles in numerous other films and television shows. Flaherty is a versatile and talented performer known for his comedic timing and ability to portray a wide range of characters.