The Mysterious Doctor

John Loder

— Sir Henry Leland

Eleanor Parker

— Letty Carstairs

Bruce Lester

— Lt. Christopher 'Kit' Hilton

Lester Matthews

— Dr. Frederick Holmes

Forrester Harvey

— Hugh Penhryn

Matt Willis

— Bart Redmond

Phyllis Barry

— Ruby

David Clyde

— Tom Andrews

Clyde Cook

— Herbert

Art Foster

— Saul Bevans

Creighton Hale

— Luke

Hank Mann

— Roger Porley

Harold De Becker

— Peddler

Stuart Holmes

— Civil Defense Officer

Crauford Kent

— Army Commander

Frank Mayo

— Simon Tewksbury

Leo White

— Headless Man

Jack Mower

— Policeman