"Lux Radio Theater" broadcast a 60 minute radio adaptation of the movie on February 27, 1937 with Errol Flynn, Olivia de Havilland, Basil Rathbone and Henry Stephenson reprising their film roles.
Basil Rathbone felt miscast as a French pirate.
Robert Donat was cast in the title role, but couldn't complete it because of chronic health health issues. 'Leslie Howard' (v) was second choice but was either unavailable or uninterested. Fredric March, Ronald Colman and Clark Gable were also considered by supervisor Harry Joe Brown. After George Brent, Brian Aherne and Errol Flynn were tested, Warners decided to take a gamble on the unknown Australian.
Errol Flynn reportedly had an affair with co-star Ross Alexander that lasted for the duration of filming.
Although they worked together a total of 12 times, Errol Flynn and Michael Curtiz disliked each other intensely.
Because Erich Wolfgang Korngold had only three weeks for scoring this picture, he used portions of two tone poems by Franz Liszt for some of the action scenes. However, he insisted on the screen credit "Musical Arrangements by" although 90% of the score was original.
Captain Blood's battles with the brother of the Spanish captain whose ship he stole, his commission to serve King James, and his commission under the French flag were all deleted from the movie version.
His first major starring role, Errol Flynn was so nervous during the initial shooting that director Michael Curtiz had to re-shoot his early scenes much later into the production, by which time Flynn had gained a level of confidence.
In his biography, "My Wicked, Wicked Ways" Errol Flynn (an infamous prankster) states that he played many pranks on Olivia de Havilland. One of them was leaving a dead snake in her underwear, which she found when she went to put them on. After that she lived in terror of what prank he would pull on her next.
In the original novel, Captain Blood and Captain Levasseur are fighting over Madamoiselle d'Onefoys and not Arabella Bishop. The two characters were combined into one to save money for the production.
Lord Willoughby is a combination of Lord Julian Wade and Lord Willoughby, the two nobleman characters from Rafael Sabatini's book.
No full-sized ships were used in the battle scenes. It was created by a combination of process shots, miniatures, and footage from the silent film, The Sea Hawk, which was based on another Rafael Sabatini novel.
The Academy Awards that year allowed write-in votes. Based on write-ins alone, Michael Curtiz would have won the Oscar for best director, but on the night he lost to John Ford for his work on The Informer. Composer Erich Wolfgang Korngold and writer Casey Robinson also failed to be properly nominated, though they both received large numbers of postal votes for their work.
The card game Bronson and Whacker are playing is Cribbage.
The first film to feature a musical score by Erich Wolfgang Korngold, one of Hollywood's greatest composers. Korngold was given three weeks to score the film, although during the day he was working on adapting the score of an operetta for Paramount called Give Us This Night. He worked nights on the score for this film.
The first of nine movies made together by Warner Brothers' romantic couple Olivia de Havilland and Errol Flynn.
The first screen duel between Errol Flynn and Basil Rathbone, to be replayed three years later and to grander effect in The Adventures of Robin Hood.
The first talkie to be based on a novel by then popular novelist Rafael Sabatini.
This was a big gamble for Warner Brothers in 1935, as it was an expensive production, costing $1 million without any household names (both Errol Flynn and Olivia de Havilland became stars after the film's release).