Ralph Morgan

as Dr. Lester Cavigny

as Dr. Rhinehart

as David Thayar

as B.B. Lavish

as Anthony Lawrence

as Prof. Millard Sawtelle

as Col. DeBoivin

as George Brett

as Jan Hanka

as Kurt Ingston

as Dr. Charles Downer

as Spiro Gregory

as Shaw MacAllen

as Briggs

as Nicholas Pryor

as Commander of Paris

as John R. Flemyng

as Yankee General

as Debrulle

as Mr. Dean

as Leroy Hutchins, War Cloud's Owner

as Randolph

as Paul Kristan

as Roger Classon

as Secretary to President

as Father

as Raymond Wrede

as Henry

as Dr. Verney

as Charlie Marsden

as Czar Nicholas II

as Riggs (uncredited)