- William Powell
- Dr. Lawrence Bradford
- Jean Arthur
- Paula Bradford
- James Gleason
- Inspector Corrigan
- Eric Blore
- Stokes
- Robert Armstrong
- Nick Martel
- Lila Lee
- Miss Prentiss
- Grant Mitchell
- John Summers
- Erin O'Brien-Moore
- Mrs. Summers
- Ralph Morgan
- Leroy Hutchins
- Lucile Gleason
- Mrs. Hutchins
- Johnny Arthur
- Mr. Frankenstein
- Stanley Blystone
- Police Radio Operator
- Tom Brower
- Police Sergeant
- Spencer Charters
- Dr. Bunting
- Frankie Darro
- Spike Salisbury
- John Dilson
- Analyst Examining Gelatin Capsule
- James Donlan
- Taxi Driver
- Jimmie Dundee
- One of Martel's Hoods
- Paul Fix
- Lou Pender
- Dorothy Granger
- Fill-in Receptionist
- Sam Hayes
- Race Announcer
- Rollo Lloyd
- Landlord
- Edward McWade
- Minister in Film
- Frank Reicher
- Henry Strand
- Charles Richman
- Mr. Curtis
- Syd Saylor
- Detective
- John Sheehan
- Bert Murphy
- Buster Slaven
- Newsboy
- Al St. John
- Morgue Attendant
- Henry Stone
- Ray Torro
- Jack Stoney
- Slim - Martel's Hood
- Bob Tansill
- Joe Jerino
- Frank M. Thomas
- Mike North
