Natural around Pittsburgh, Flaherty emigrated to Toronto, Canada to start his comedy career with a Toronto Second City theatre troupe. He spent eight years on the indicate, swimming such characters when Heavy Jim McBob (of Domestic Film Report fame), Count Floyd/Floyd Robertson (the latter existence a burlesque of CBC newsman Lloyd Robertson), and station manager Guy Caballero world health organization goes around inside the wheelchair simply for the respect therein. He left a indicate inside 1984.

Throughout his film career, Flaherty has appeared within a total of cult favourites, virtually all notably swimming the a portion of the Western Union postal worker who delivers Doc Brown's 70-year-old letter to Marty McFly in the unforgettable climax of 1989's Back to the Future Part II.

Around 1999, Flaherty joined the cast of Freaks and Geeks, an NBC hourlong dramedy in which he played Harold Weir, the irascible father of 2 teens. (He would typically lecture the babies sustaining cautionary tales last, "You know where he is now? He's dead!") Despite the dedicated cult following, the indicate simply lasted of these year.

As of 2004, Flaherty is a member of the faculty at Humber College, where he teaches the comedy writing course. He is likewise on the program's Advisory Committee.

Selected filmography
Home on the Range (2004) National Security (2003) Slackers (2002) Detroit Rock City (1999) Happy Gilmore (1996) ''Who's Harry Crumb? (1989) Back to the Future Part II (1989) Innerspace (1987) One Crazy Summer (1986) Club Paradise (1986) Follow That Bird (1985) Stripes (1981) Heavy Metal'' (1981) (voice)