| Person | Type | Job | Role(s) |
|---|---|---|---|
 Alexandre Dumas | Crew | Writing | Novel |
 Anchise Brizzi | Crew | Camera | Director of Photography |
 Charles Bennett | Crew | Writing | Screenplay |
 Dario Sabatello | Crew | Production | Associate Producer |
Don L. Cash | Crew | Costume & Make-Up | Makeup Artist |
Edward Small | Crew | Production | Executive Producer |
Fred R. Feitshans Jr. | Crew | Editing | Editor |
Georges Annenkov | Crew | Costume & Make-Up | Costume Design |
Gino Brosio | Crew | Art | Set Decoration |
 Gregory Ratoff | Crew | Directing | Director, Producer |
James C. McKay | Crew | Editing | Editor |
 Otello Martelli | Crew | Camera | Director of Photography |
Ottavio Scotti | Crew | Art | Art Direction |
Paul Sawtell | Crew | Sound | Music |
Renzo Lucidi | Crew | Editing | Editor |
Richard Schayer | Crew | Writing | Screenplay |
Ubaldo Arata | Crew | Camera | Director of Photography |
Vittorio Nino Novarese | Crew | Costume & Make-Up | Costume Design |
Jean-André d'Eaubonne | Crew | Art | Art Direction |
 Akim Tamiroff | Cast | Actor | Gitano |
Annielo Mele | Cast | Actor | Joseph Balsamo as a Child |
 Berry Kroeger | Cast | Actor | Alexandre Dumas, Sr. |
 Bruce Belfrage | Cast | Actor | Crown Prosecutor |
 Charles Goldner | Cast | Actor | Dr. Franz Anton Mesmer |
Franco Corsaro | Cast | Actor | Chico |
 Frank Latimore | Cast | Actor | Gilbert de Rezel |
Giuseppe Varni | Cast | Actor | Boehmer |
 Gregory Gaye | Cast | Actor | Chambord / Monk (as Gregory Gay) |
 Harriet Medin | Cast | Actress | (uncredited) |
Joop van Hulzen | Cast | Actor | Minister of Justice |
 Leonardo Scavino | Cast | Actor | Gaston / Beniamino Balsamo (as Leon Lenoir) |
 Ludmilla Dudarova | Cast | Actress | (uncredited) |
 Margot Grahame | Cast | Actress | Mme. du Barry |
Michele Sakara | Cast | (uncredited) | |
 Milly Vitale | Cast | Actress | (uncredited) |
 Nancy Guild | Cast | Actress | Marie Antoinette / Lorenza |
Nicholas Bruce | Cast | Actor | De Remy |
 Nicholas Soussanin | Cast | Actor | (uncredited) |
 Orson Welles | Cast | Actor | Joseph Balsamo aka Count Cagliostro |
Peter Trent | Cast | Actor | Dr. Mesmer's Friend |
 Raymond Burr | Cast | Actor | Alexandre Dumas, Jr. |
Robert Atkins | Cast | Actor | King Louis XV |
 Ronald Adam | Cast | Actor | Court President |
 Rosina Galli | Cast | Actress | (uncredited) |
 Silvana Mangano | Cast | Actress | (uncredited) |
 Stephen Bekassy | Cast | Actor | Viscount de Montagne |
 Tamara Shayne | Cast | Actress | Maria Balsamo |
 Tatyana Pavlova | Cast | Actress | Grieving Mother |
 Valentina Cortese | Cast | Actress | Zoraida |
Lee Kresel | Cast | Actor | King Louis XVI / Innkeeper |
Filippo Minelli | Cast | (uncredited) | |
Alexander Danaroff | Cast | Dr. Duval / Baron von Minden | |
Valentino Bruchi | Cast | Actor | (uncredited) |
| Person | Type | Job | Role(s) |
