Marlon Brando was briefly considered for the role of the King of Siam.
Marni Nixon was hired on a six-week contract, and she was to be at the studio every day that Deborah Kerr rehearsed a scene with a song in it. Nixon would actually stand next to Kerr and walk through the whole scene - both of them singing - and Nixon would be looking closely at Kerr's facial expressions to try to imitate her speech pattern in the songs.
Yul Brynner is the only man to have played a lead role in a Richard Rodgers and Oscar Hammerstein II production both on the stage and on the screen.
Yul Brynner won the 1952 Tony Award (New York City) for Supporting or Features Actor in a Musical for "The King and I" as the King of Siam and recreated his role in the movie version.
Darryl F. Zanuck first cast Maureen O'Hara as Anna because she was not only gorgeous but had a fine soprano voice and would not have to be dubbed. When Zanuck told her the news, she immediately sent sample recordings of her voice. Richard Rodgers agreed that O'Hara had a great voice but reportedly said, "No pirate queen is going to play my Anna!"
Patrick Adiarte made his film debut as Prince Chulalongkorn.
Dinah Shore, who was a singer as well as an actress, was initially considered for the role of Anna Leonowens.
Deborah Kerr's gowns, designed by Irene Sharaff, each weighed between 30 and 40 pounds, due to all the pleats, hoops and petticoats.
Deborah Kerr's signature in cement for Grauman's Chinese Theater in Hollywood was actually cast on the set of The King and I and not at the theater.
Deborah Kerr's uncredited voice double Marni Nixon said that she realized the keys of Anna's songs were very low for her - "very contralto keys" - and that she was really too young (just 21) to be able to sound "adult" and "womanly". Hence, a modifier was placed in Nixon's microphone, to make her voice sound deeper and more mature. "I have a very light, bright ring to my voice, and I tried to take that out" she said. "But they were able to use this modifier to emphasize the lower partials of my voice. I also remember having a terrible cold at the time, not being able to breathe in those recording sessions. But that probably helped in matching Deborah's voice, deepening it."
Maureen O'Hara was originally meant to play the lead role in the movie version of "The King and I", but Yul Brynner specifically asked for Deborah Kerr.
Dorothy Dandridge was the original choice for the role of Tuptim. It has been reported that Miss Dandridge, who had just made history as the first African American woman to be nominated for an Academy Award for Best Actress in Carmen Jones, was strongly advised to refuse the role because Tuptim was a slave. The role went to Rita Moreno, who was of Puerto Rican descent.
Rita Moreno said that the heavy Siamese headdresses she and the ballet dancers wore in "The Small House of Uncle Thomas" ballet sequence gave all of them headaches, which lasted for days.
According to Maureen O'Hara's autobiography, 20th Century Fox had actually cast her for the starring role, but Richard Rodgers objected and said "I won't have that pirate queen playing our Anna."
Although Walter Lang is given sole directorial credit on the film, Yul Brynner repeatedly clashed with him and made many of the directorial suggestions which found their way into the finished film.
Although this movie was filmed and promoted in the then-new 55 mm CinemaScope 55, it was actually shown in the standard 35 mm CinemaScope, with 4-channel stereo rather than the 6-channel stereo originally promised. CinemaScope 55 was discarded after being used on only two feature films (this and Carousel).
Art directors John DeCuir and Lyle R. Wheeler spent $750,000 designing the 40 sets required for the film.
At one point, Fox executives suggested that the story be changed so that the King would be gored by a white elephant, rather than become ill because of a personal humiliation. Understandably, this made Yul Brynner furious, and he insisted that the story stick to the stage version.