Prior to the United States' involvement in World War II, the masked vigilante Spy Smasher fights Nazi agents operating within the US, led by the treacherous sabotage leader codenamed The Mask.
| Actor | Role |
|---|---|
 Kane RichmondAlan Armstrong / Jack Armstrong | Alan Armstrong / Jack Armstrong |
 Marguerite ChapmanEve Corby | Eve Corby |
 Sam FlintAdmiral Corby | Admiral Corby |
 Hans SchummThe Mask | The Mask |
 Tristram CoffinDrake | Drake |
| FFranco CorsaroCaptain Pierre Durand | Captain Pierre Durand |
| HHans von MorhartCaptain Gerhardt | Captain Gerhardt |
 Georges RenaventGovernor LeComte | Governor LeComte |
 Rudolph AndersCol. Von Kohr | Col. Von Kohr |
| HHenry ZyndaRitter Lazar | Ritter Lazar |
 Paul BryarLawlor | Lawlor |
 Tom LondonCrane | Crane |
 Richard BondHayes | Hayes |
 Crane WhitleyHauser | Hauser |
 John JamesSteve | Steve |
 Dudley DickersonTrain Porter (uncredited) | Train Porter (uncredited) |
 William ForrestThornton (uncredited) | Thornton (uncredited) |
 Yakima CanuttArmored Car Driver (uncredited) | Armored Car Driver (uncredited) |
| AArvon DaleThornton (uncredited) | Thornton (uncredited) |