Sully's first major role came in 1941 for Monogram Pictures, a "budget" studio that often gave opportunities to ambitious actors.

[1] In the Frankie Darro campus comedy Let's Go Collegiate, Sully was featured as a dumb truck driver recruited to masquerade as a star athlete.

The Exhibitor noted that "Sully takes acting honors, with Darro, (Keye) Luke, and (Jackie) Moran very good in their roles.

[3] He supported star comedians Hugh Herbert, Vera Vague, Slim Summerville, Wally Vernon and Eddie Quillan, Joe Besser, and most memorably The Three Stooges.

Credits include Maverick, The Alfred Hitchcock Hour, Leave It to Beaver, I Love Lucy and The Beverly Hillbillies and "Charley" on Topper.