Audrey Hepburn was originally offered the role of Joan. Rumor had it she turned it down because her husband, Mel Ferrer, wasn't offered the role of the Dauphin, but Ferrer denied this.
Screenwriter Graham Greene, a famous author, added some lines to the original Shaw play when he adapted it for this movie, such as Warwick's "She'll burn, before the Pope gets to hear of it!"
During pre-production, Director Otto Preminger had considered using English actors for English characters, and Irish actors for the French.
Neophyte Jean Seberg was selected by Otto Preminger from a host of unknowns to make her screen debut in the titular role. Though she survived lukewarm notices for her work, Seberg would survive for fifteen years in Hollywood. Her tragic end would conform to a pattern that haunted the majority of leading ladies discovered by Preminger, including Jill Haworth, Maggie McNamara, and Dorothy Dandridge, all of whom either committed suicide or died young.
Jean-Luc Godard's appreciation for this and Bonjour Tristesse (1958) led Jean Seberg to be cast as the lead in Breathless (1960).
A special effects accident caused Jean Seberg to actually to catch on fire during the pivotal scene where Joan of Arc is burned at the stake. Seberg sustained only minor injuries. On screen is the very disturbing moment when her neck catches on fire, and Joan looks understandably shaken, but she does not scream or cry out, during the burning.
Paul Scofield quit after a disagreement with Director Otto Preminger during the first cast read-through.
In George Bernard Shaw's original play, first staged in 1923, a character in the epilogue mentions the then-recent canonization of Joan (this happened in 1920). Among Graham Greene's revisions to the play is to have the epilogue mention the Nazi occupation of Paris.