John Kapelos has been extensively involved with Second City improvisational troupe throughout his career. Kapelos made his film debut as Mechanic #3 in the 1981 neo-noir crime drama "Thief." Following this appearance with bit parts in "Tootsie" and "Class," Kapelos came into the orbit of Chicago filmmaker John Hughes, who cast him in three of his motion pictures-"Sixteen Candles," "Weird Science," and "The Breakfast Club," the last of which provided Kapelos with his best-known role as Carl the Janitor. He spent the remainder of the 1980s and the beginning of the 1990s balancing comedy appearances alongside Steve Martin ("Roxanne") and Tom Hanks ("Nothing in Common") with dramatic exchanges with James Woods ("The Boost") and Richard Gere ("Internal Affairs"). Back in his home country, a fan base developed over his portrayal of Detective Don Schanke in the 1989 detective vampire series, "Forever Knight." In the United States, his theatrical versatility allowed him to work within a broad range of television genres including kids shows ("iCarly"), sci-fi ("The X-Files"), classic sitcoms ("Seinfeld"; "Home Improvement"), medical dramas ("ER"), and legal dramedy ("Boston Legal").