Edward G. Robinson as John Triton

Gail Russell as Jean Courtland

John Lund as Elliott Carson

Virginia Bruce as Jenny

William Demarest as Lt. Shawn

Richard Webb as Peter Vinson

Jerome Cowan as Whitney Courtland

Onslow Stevens as Dr. Walters

John Alexander as Mr. Gilman

Roman Bohnen as Special Prosecutor Melville Weston

Luis van Rooten as Mr. Myers

Henry Guttman as Butler

Mary Adams as Miss Hendricks the Housekeeper

Douglas Spencer as Dr. Ramsdell

Dorothy Abbott as Maid (uncredited)

Jimmie Dundee as Policeman (uncredited)

Julia Faye as Companion (uncredited)

Pat Flaherty as Policeman (uncredited)

Frank Hagney as Truckman (uncredited)

Minerva Urecal as Elderly Italian Woman (uncredited)

Margaret Field as Agnes (uncredited)

Stuart Holmes as Scientist (uncredited)