The movie's line "I stick my neck out for nobody." was voted as the #42 of "The 100 Greatest Movie Lines" by Premiere in 2007.
The movie's line "Louis, I think this is the beginning of a beautiful friendship." was voted as the #20 movie quote by the American Film Institute
The movie's line "Louis, I think this is the beginning of a beautiful friendship." was voted as the #65 of "The 100 Greatest Movie Lines" by Premiere in 2007.
The movie's line "Of all the gin joints in all the towns in all the world, she walks into mine." was voted as the #67 movie quote by the American Film Institute (out of 100).
The movie's line "Round up the usual suspects." was voted as the #32 movie quote by the American Film Institute (out of 100).
The movie's line "We'll always have Paris." was voted as the #43 movie quote by the American Film Institute (out of 100).
The music heard over the film's opening credits was a retread: composer Max Steiner had originally written and used the theme for the 1934 John Ford film, The Lost Patrol. Steiner slightly altered the tempo and instrumentation of this theme music for Casablanca.
The opening street bazaar scenes were filmed on the same studio backlot built and used for The Desert Song a few months previously.
The original unproduced play, "Everybody Comes to Rick's", was found by Irene Lee, who headed the story department at Warner Bros., on a trip to office of Jack Wilk, story editor for Warner East Coast operations in New York, where the typed script had sat for a year. It arrived at Warner Bros. Studios to be read as a potential film project on the day after the Japanese bombed Pearl Harbor.
The Paris train station set was recycled from Now, Voyager.
The scene of Maj. Strasser's arrival was filmed at Metropolitan Airport, now known as Van Nuys Airport, just outside of Los Angeles.
The script was based on the unproduced play "Everybody Comes to Rick's". Samuel Marx of MGM wanted to offer authors (Murray Burnett and Joan Alison) $5,000 for it, but MGM boss Louis B. Mayer refused; Irene Lee of the Warner Brothers story department praised it to Jack L. Warner, who agreed to buy it for $20,000.
The song "As Time Goes By" from the film is number 2 on the American Film Institute's (AFI) 100 Years... 100 Songs list.
The title was changed from "Everybody Comes to Rick's" to Casablanca partly due to the success of the similarly titled Algiers.
To maximize profits from foreign distribution of the film, the studio suggested that any unpleasant characters other than the Nazis should also be from an enemy country, namely Italy. This is why Ugarte, Ferrari, and the dark European pickpocket are Italian.
Venerable character actor Clarence Muse, who lost the role of Sam to Dooley Wilson, played the role in the 1955 TV series. Ludwig Stössel was promoted from the minor role of Leuchtag to the S.Z. Sakall part (renamed Ludwig), Marcel Dalio was elevated from the minor role of Emil, the croupier, to the Claude Rains role (renamed Renaud), and Dan Seymour was promoted from the small part of Abdul to Ferrari, the Sydney Greenstreet role.
Voted #2 film of all time by the American Film Institute.
Warner Bros. had intended to use the "Horst-Wessel-Lied", the anthem of the Nazi party, during the "battle of the anthems" sequence, but the copyright was controlled by a German company, and Warners dropped that anthem for the 1840s song "Die Wacht Am Rhein" (about a vow to defend the Rhineland from a French invasion) rather than violate the rights (which would have prompted the German copyright holder on the song to prohibit the movie from being shown in any country not at war with Germany).
Warner Brothers purchased the play for $20,000, the most anyone had ever paid for an unproduced work.