Donovan's Brain

Lew Ayres

Dr. Patrick J. Cory

Nancy Reagan

Janice Cory

Gene Evans

Dr. Frank Schratt

Steve Brodie

Herbie Yocum

Tom Powers

Donovan's Washington Advisor

Lisa Howard

Chloe Donovan

James Anderson

Chief Tuttle

Victor Sutherland

Nathaniel Fuller

Michael Colgan

Tom Donovan

Peter Adams

Mr. Webster

Harlan Warde

Treasury Agent Brooke

Shimen Ruskin

Tailor

John Hamilton

Mr. McNish (uncredited)

Don Brodie

Detective Who Follows Dr. Cory from Hotel (uncredited)

Stapleton Kent

W. J. Higgins (uncredited)

Frank McLure

Man leaving Fuller's Office (uncredited)