Casablanca received "consistently good reviews". Bosley Crowther of The New York Times wrote, "The Warners... have a picture which makes the spine tingle and the heart take a leap." The newspaper applauded the combination of "sentiment, humor and pathos with taut melodrama and bristling intrigue". While he noted its "devious convolutions of the plot", he praised the screenplay quality as "of the best" and the cast's performances as "all of the first order".
The trade paper Variety commended the film's "combination of fine performances, engrossing story and neat direction" and the "variety of moods, action, suspense, comedy and drama that makes Casablanca an A-1 entry at the b.o." "Film is splendid anti-Axis propaganda, particularly inasmuch as the propaganda is strictly a by-product of the principal action and contributes to it instead of getting in the way." The review also applauded the performances of Bergman and Henreid and note that "Bogart, as might be expected, is more at ease as the bitter and cynical operator of a joint than as a lover, but handles both assignments with superb finesse."
Some other reviews were less enthusiastic. The New Yorker rated it only "pretty tolerable".
The film has grown in popularity. Murray Burnett called it "true yesterday, true today, true tomorrow". By 1955, the film had brought in $6.8 million, making it the third most successful of Warners' wartime movies (behind Shine On, Harvest Moon and This Is the Army). On April 21, 1957, the Brattle Theater of Cambridge, Massachusetts, showed the film as part of a season of old movies. It was so popular that it began a tradition of screening Casablanca during the week of final exams at Harvard University, which continues to the present day. Other colleges have adopted the tradition. Todd Gitlin, a professor of sociology who had attended one of these screenings, has said that the experience was "the acting out of my own personal rite of passage". The tradition helped the movie remain popular while other famous films of the 1940s have faded away. By 1977, Casablanca was the most frequently broadcast film on American television.
On the film's 50th anniversary, the Los Angeles Times called Casablanca's great strength "the purity of its Golden Age Hollywoodness [and] the enduring craftsmanship of its resonantly hokey dialogue". Bob Strauss wrote in the newspaper that the film achieved a "near-perfect entertainment balance" of comedy, romance, and suspense.
According to Roger Ebert, Casablanca is "probably on more lists of the greatest films of all time than any other single title, including Citizen Kane" because of its wider appeal. Ebert opined that Citizen Kane is generally considered to be a "greater" film but Casablanca is more loved. In his opinion, the film was popular because "the people in it are all so good", and it was "a wonderful gem". Ebert said that he has never heard of a negative review of the film, even though individual elements can be criticized, citing unrealistic special effects and the stiff character/portrayal of Laszlo. Critic Leonard Maltin considers Casablanca to be "the best Hollywood movie of all time."
Rick, according to Rudy Behlmer, is "not a hero ... not a bad guy": he does what is necessary to get along with the authorities and "sticks his neck out for nobody". The other characters, in Behlmer's words, are "not cut and dried" and come into their goodness over the course of the film. Renault begins as a collaborator with the Nazis who extorts sexual favors from refugees and has Ugarte killed. Even Ilsa, the least active of the main characters, is "caught in the emotional struggle" over which man she really loves. By the end, however, "everybody is sacrificing." Behlmer also emphasized the variety in the picture: "it's a blend of drama, melodrama, comedy [and] intrigue".
A few reviewers have had reservations. According to Pauline Kael, "It's far from a great film, but it has a special appealingly schlocky romanticism..." Umberto Eco wrote that "by any strict critical standards... Casablanca is a very mediocre film." He viewed the changes the characters undergo as inconsistent rather than complex: "It is a comic strip, a hotch-potch, low on psychological credibility, and with little continuity in its dramatic effects." However, he added that due to the presence of multiple archetypes which allow "the power of Narrative in its natural state without Art intervening to discipline it", it is a movie reaching "Homeric depths" as a "phenomenon worthy of awe."
In the November/December 1982 issue of American Film, Chuck Ross claimed that he retyped the screenplay to Casablanca, changing the title back to Everybody Comes to Rick's and the name of the piano player to Dooley Wilson, and submitted it to 217 agencies. Eighty-five of them read it; of those, thirty-eight rejected it outright, thirty-three generally recognized it (but only eight specifically as Casablanca), three declared it commercially viable, and one suggested turning it into a novel.
Influence on later works
Many subsequent films have drawn on elements of Casablanca. Passage to Marseille reunited Bogart, Rains, Curtiz, Greenstreet and Lorre in 1944. There are similarities between Casablanca and two later Bogart films, To Have and Have Not (1944) and Sirocco (1951).
Parodies have included the Marx Brothers' A Night in Casablanca (1946), Neil Simon's The Cheap Detective (1978), and Out Cold (2001). It provided the title for the 1995 hit The Usual Suspects. Woody Allen's Play It Again, Sam (1972) appropriated Bogart's Casablanca persona as the fantasy mentor for Allen's nebbishy character, featuring actor Jerry Lacy in the role of Bogart.
The film Casablanca was a plot device in the science-fiction television movie Overdrawn at the Memory Bank (1983), based on John Varley's story. It was referred to in Terry Gilliam's dystopian Brazil (1985). Warner Bros. produced its own parody in the homage Carrotblanca, a 1995 Bugs Bunny cartoon. In Casablanca, a novella by Argentine writer Edgar Brau, the protagonist somehow wanders into Rick's Café Americain and listens to a strange tale related by Sam.