Basil Rathbone, being a well known fencer in his own right, was asked how well Tyrone Power did in their scenes in which stunt doubles were not used. Rathbone responded, "Tyrone Power could fence Errol Flynn into a cocked hat!"
The famous duel was staged by Hollywood fencing master Fred Cavens. Cavens specialized in staging duels that relied more on actual swordplay rather than the jumping on furniture and leaping from balconies that many film "duels" consisted of up until that point. Cavens' son, Albert Cavens, doubled for Tyrone Power in the fancier parts of the duel (mostly with his back to camera), such as the extended exchange with Esteban ending with Don Diego's sword smashing into the bookcase. Basil Rathbone, a champion fencer in real life, did not care for the saber (the weapon of choice in this film), but nevertheless did all of his own fencing. Fast fencing shots were undercranked to 18 or 20 frames per second (as opposed to the standard 24fps) and all the sound effects were post-synchronized.
During filming, Tyrone Power was in the habit of taking an early morning swim in a pool that he insisted on being carefully pre-heated. Darryl F. Zanuck played a prank on him by arranging for the heating to be turned off. Power dived in and got such a shock that he later claimed he nearly had a heart attack. He got his revenge. Zanuck watched the dailies every day with a critical eye and one evening saw something unexpected; the cast and crew collaborated to film a spoof version of the hold-up scene where Zorro robs a coach carrying the Governor and his wife. When Zorro is supposed to slash his trademark "Z" into the coach's seat cushion, the reverse angle reveals an uncharacteristic "DZ" instead, to a shocked gasp of "Zanuck!" from J. Edward Bromberg, as the evil Alcalde. Power declares snidely, "Let that be a lesson to you, damn it!"
In the DC Comic continuity it is established that 'The Mark of Zorro' was the film that the young Bruce Wayne had seen with his parents at a movie theater, moments before they were killed in an armed thug.
The film is based on "The Curse of Capistrano", written by Johnston McCulley, originally published in 1919 in five serialized installments in "All-Story Weekly", which introduced the masked hero Zorro; the story is set in Southern California during the early 19th century.