Hugh Beaumont as Dennis O'Brien

Ann Savage as Ann Harmon

Edward Brophy as Prof. Shicker

Richard Travis as Police Inspector Lt. Bruger

Margia Dean as Flo Klingle

Mike Mazurki as Ape Danowski

David Bruce as Charles Giffen

Raymond Greenleaf as Father Donovan

Eve Miller as Norma Harmon

Harry Hayden as Dr. Earl J. Tomkins

Joi Lansing as The Cocktail Waitress

Peter Mamakos as Nick Garrison

Chris Drake as Mike Greeley

Billy Varga as Willie Klingle

John Indrisano as Mushy Cavelli

Richard Monahan as Henry - Bartender

Charles Wagenheim as Lefty - Policy Man

Jack Chefe as Waiter (uncredited)

Heinie Conklin as Counter Man (uncredited)

Jack Gordon as Wrestling Match Spectator (uncredited)

Kit Guard as Drunk at Wrestling Match (uncredited)

Barry Norton as Waiter (uncredited)

Cosmo Sardo as Club patron (uncredited)

Max Wagner as Bar Patron (uncredited)