 Boris KarloffDr. Friedrich Hohner | Dr. Friedrich Hohner |
 Susanna FosterAngela Klatt | Angela Klatt |
 Turhan BeyFranz Munzer | Franz Munzer |
 Gale SondergaardLuise | Luise |
 Thomas GomezCount Seebruck | Count Seebruck |
 June VincentMarcellina | Marcellina |
 George DolenzAmato Roselli | Amato Roselli |
 Ludwig StösselCarl Baumann | Carl Baumann |
 Jane FarrarJarmila Vadek | Jarmila Vadek |
 Ernö VerebesBrunn | Brunn |
 Lotte SteinMama Hinzl | Mama Hinzl |
 Scotty BeckettThe King | The King |
 William EdmundsLeon, Theatre Concierge | Leon, Theatre Concierge |
| MMaxwell HayesCount Romburg | Count Romburg |
| DDorothy LawrenceMiss Metzger | Miss Metzger |
| BBella LewitzkyDancer (Uncredited) | Dancer (Uncredited) |
 Jack RichardsonMusical Conductor (Uncredited) | Musical Conductor (Uncredited) |
| PPolly BaileyCleaning Woman (Uncredited) | Cleaning Woman (Uncredited) |
 Stuart HolmesKing's Consul (Uncredited) | King's Consul (Uncredited) |
 Eddie PoloStagehand (Uncredited) | Stagehand (Uncredited) |
| PPaul PowerReporter (Uncredited) | Reporter (Uncredited) |
 Ernie AdamsMan in Audience Next to Franz (Uncredited) | Man in Audience Next to Franz (Uncredited) |
 Gertrude AstorWoman in Audience Behind Franz (Uncredited) | Woman in Audience Behind Franz (Uncredited) |
 Grace CunardBackstage Maid (Uncredited) | Backstage Maid (Uncredited) |
 William DesmondBackstage Technician (Uncredited) | Backstage Technician (Uncredited) |
 Francis FordBackstage Attendant (Uncredited) | Backstage Attendant (Uncredited) |
 Louis PayneAudience Member (Uncredited) | Audience Member (Uncredited) |
 Anne CornwallAudience Member (Uncredited) | Audience Member (Uncredited) |
 Rudy BowmanAudience Member (Uncredited) | Audience Member (Uncredited) |
 William H. O'BrienAudience Member (Uncredited) | Audience Member (Uncredited) |
