The screenplay by George Oppenheimer and Harry Kurnitz, based on a story by Herbert Dalmas, has uncredited contributions by William Faulkner and Robert Florey.

The Spanish ambassador in London, Count de Polan, an old family friend, sends a letter of recommendation to Queen Margaret of Spain.

He requests that she provide an opportunity at the Spanish court for the rehabilitation of Don Juan's reputation from the swirling gossip and scandal that have followed him around Europe in the wake of his many illicit love affairs.

Accepting her old friend's suggestion, Queen Margaret thus appoints Don Juan as a fencing instructor to the Royal Spanish Academy, where he is a great success.

During his time at court, he secretly falls in love with the Queen but remains a staunchly loyal subject to her and her irresponsible and weak husband, King Philip III.

With the support of his friends at court, Don Juan heroically defends the Queen and the King against de Lorca and his henchmen, finally defeating his plan in a duel to death, saving Spain.

Warners stated Olivia de Havilland, Priscilla Lane, Margaret Lindsay, Ann Sheridan, and Lya Lys would appear in the film, along with five other actresses.

Flynn did fencing training with Fred Cravens, and George Coulouris (the intended main villain) did extensive dieting for the role.

[15] Filming was postponed due to difficulty in sourcing costumes (there was a general post-war shortage) and an industry strike that affected construction and painting of sets.

Warner Bros were encouraged to re-activate the film again by a successful 1947 reissue of Flynn's earlier starring vehicles, The Adventures of Robin Hood (1938) and The Sea Hawk (1940).

Flynn didn't agree with me at all because he still wanted to be the wonderful guy who jumps out the window pursued by the irate husband saying 'You made love to my wife' and all that.

"[26] Errol Flynn was suffering from poor health, reportedly from a mild heart condition and recurrent bouts of hepatitis.

In the famous on-screen leap from the head of a long staircase, Flynn was doubled by stunt expert Jock Mahoney.

[32] In the silent film Don Juan (1926), Flynn's idol John Barrymore performed a similar leap without a stunt double.

At the end of the picture, the young woman in the coach asking Don Juan for directions is Flynn's wife, Nora Eddington.

The score was adapted years later by composer Ian Fraser for the George Hamilton swashbuckling comedy film Zorro, The Gay Blade (1981).

The loves and escapades of the fabulous Don Juan are particularly adapted to the screen abilities of Errol Flynn and he gives them a flair that pays off strongly.

"[36][37] Harrison's Reports called the film "trite both in story and treatment", but "should go over pretty well with those who enjoy colorful pageantry with plenty of glittering swordplay and exciting chases.

"[38] John McCarten of The New Yorker called it "a picture that demonstrates once again that Errol Flynn is muscular as all get out but quite innocent of any ability in the acting line.