Orson Welles
Joseph Balsamo aka Count Cagliostro
Nancy Guild
Marie Antoinette / Lorenza
Akim Tamiroff
Gitano
Frank Latimore
Gilbert de Rezel
Valentina Cortese
Zoraida
Margot Grahame
Mme. du Barry
Stephen Bekassy
Viscount de Montagne
Berry Kroeger
Alexandre Dumas, Sr.
Gregory Gaye
Chambord / Monk (as Gregory Gay)
Raymond Burr
Alexandre Dumas, Jr.
Charles Goldner
Dr. Franz Anton Mesmer
Lee Kresel
King Louis XVI / Innkeeper
Robert Atkins
King Louis XV
Nicholas Bruce
De Remy
Franco Corsaro
Chico
Annielo Mele
Joseph Balsamo as a Child
Ronald Adam
Court President
Bruce Belfrage
Crown Prosecutor
Alexander Danaroff
Dr. Duval / Baron von Minden
Leonardo Scavino
Gaston / Beniamino Balsamo (as Leon Lenoir)
Tamara Shayne
Maria Balsamo
Joop van Hulzen
Minister of Justice
Peter Trent
Dr. Mesmer's Friend
Giuseppe Varni
Boehmer
Tatyana Pavlova
Grieving Mother
Harriet Medin
(uncredited)
Valentino Bruchi
(uncredited)
Ludmilla Dudarova
(uncredited)
Rosina Galli
(uncredited)
Silvana Mangano
(uncredited)
Filippo Minelli
(uncredited)
Michele Sakara
(uncredited)
Nicholas Soussanin
(uncredited)
Milly Vitale
(uncredited)