Born and raised in Ontario, Canada, Rob Stefaniuk began acting in community theater productions. While still in his teens, he landed his first television guest appearance on an episode of the crime series, Katts and Dog. Next he played Dave in the U.S. TV movie Blown Away (1992), filmed in Toronto and starring Nicole Eggert, Corey Feldman and Corey Haim. In 1994 he joined the cast of the MTV teen drama series Catwalk for its last season. Other TV credits include The Kids in the Hall, Street Legal, Forever Knight, Kung Fu: The Legend Continues, Monk, Mutant X and Timothy Goes to School.
At the age of 23, Rob wrote his first screenplay, The Size of Watermelons, which was produced as an independent feature in 1996. He was story editor and line producer on his girlfriend Kris Lefcoe's independent feature, Public Domain (2003). Inspired by the process, he made his own directorial debut with a short, Waiting for the Man (2003). The film, featuring a beaver and a sheep engaged in an existential discussion while waiting for a mysterious third party, was chosen to be screened at the 2004 Worldwide Short Film Festival in the Canadian Competition.
Stefaniuk made his feature film directorial debut with his own screenplay, Phil the Alien (2005), about an alien and a beaver. He also wrote some of the soundtrack, and after searching for a celebrity to play the lead, finally decided to play the role himself. For his second feature, Suck, Stefaniuk again wrote songs for the soundtrack and played the lead, but managed to get stars such as Dave Foley, Jessica Paré, Alice Cooper, Carole Pope, Moby and Iggy Pop to join him. His success continued when the film was picked up at the 2009 Toronto International Film Festival for distribution in Canada by Alliance Films.