John Francis Dunsworth was a Canadian actor and filmmaker. He was best known for playing trailer park supervisor Jim Lahey, the antagonist on the comedy series Trailer Park Boys (2001–2018). His other roles included the mysterious reporter Dave Teagues on the supernatural drama series Haven (2010–2015) and Officer McNabb in the CBC film Shattered City: The Halifax Explosion (2003). He also had extensive experience in regional theater.

Trailer Park Boys is a Canadian mockumentary television sitcom created by Mike Clattenburg that began airing in 2001 as a continuation of his 1999 film bearing the same name. The show follows the misadventures of a group of trailer park residents, including two lead characters in and out of prison, living in the fictional "Sunnyvale Trailer Park" in Dartmouth, Nova Scotia. The series premiered on Showcase on April 20, 2001, and originally ran for seven seasons before concluding with a one-hour special on December 7, 2008. The series spawned three films: The Movie, released on October 6, 2006; Countdown to Liquor Day, released on September 25, 2009; and Don't Legalize It, released on April 18, 2014.