The film went into production by March 1951, and photography began June 18, 1951. But Gene Kelly caused significant changes in the script. He envisioned the film as primarily a dance film and wanted the dancer Donald O'Connor as his sidekick Cosmo. Kelly's role expanded to co-director, choreographer, actor, singer, dancer. He had two new songs written: "Make 'em Laugh" to feature O'Connor's solo talents, and a big production song medley that would include modern dance and ballet, similar to what he had done with director Vincente Minnelli in An American in Paris. In that film, the big production number based on George Gershwin's modern song was 17 minutes long and cost more that the all of the rest of the film. The film was a success and became one of MGM's top-grossing musicals ($4.5 million). Kelly was given permission to do the same thing for Singin' in the Rain. Because Debbie Reynolds could not dance, Kelly hired Cyd Charisse for the big number that would cost $600,000 and take two weeks to film, involving airplane engines blowing a 50-foot scarf that coils around Kelly and Chrarisse as they perform an abstract ballet piece as part of the "Broadway Melody" medley.
Kelly changed the film from a traditional catalogue musical to a new type of integrated musical, with songs and story tightly woven together, mixing romance and drama and comedy with modern dance. Kelly and the writiers insisted on historical accuracy for the portrayal of Hollywood's sound revolution, using original equipment if it could be found or exact replicas of the Cooper-Hewitt lights and camera booth. An old glass sound stage was found and put back into use. The furniture from John Gilbert's and Greta Garbo's 1927 Flesh and the Devil was used in Don Lockwood's home set. Kelly was quoted as saying "Almost everything in Singin' in the Rain springs from the truth. It is a conglomeration of bits of movie lore."
The film finished production November 21, 1951, and previewed in December before general release. Kelly would spend the next 18 months in Europe due to the blacklist and the HUAC committee's investigation of Kelly, Comden, Green, the Revuers cabaret group of Greenwich Village founded by Adolph Green and Judy Holliday, who testified before the Senate McCarran Committee on March 26, 1952. Also under investigation were Kelly's wife Betsy Blair who had joined the Committee to Elect Henry Wallace, and Kelly's friends among the "unfriendly 19" who were subpoenaed in 1948 by the California Fact-Finding Committee of Jack Tenney because of their membership in the pro-Wallace Progressive Citizens of America and the Committee for the First Amendment. Kelly was VP of the PCA and the Hollywood Democratic Committee, and had been an officer of the Screen Actors Guild during the strikes of 1946, and was a member of People's Songs with Pete Seeger and Woody Guthrie who wrote songs for the Wallace campaign. Kelly was on the blacklist following an article in American Legion Magazine by the journalist J. B. "Doc" Matthews that attacked Singin' in the Rain as a pro-communist movie. He was finally cleared to return to work on Brigadoon in Hollywood through the efforts of the right-wing union boss Roy Brewer, leader of the IATSE local of the mafia-dominated AFL in 1951.
Singin' in the Rain was profitable for MGM in 1952, and has been ranked as one of the greatest musical films of all time. It was featured prominantly in MGM's three That's Entertainment films of 1974, 1976, 1994, and was widely shown on television. It was praised by the French New Wave auteur theory critics who included Gene Kelly as one of the great Hollywood musical innovators with the likes of Vincente Minnelli. It became one of the best-known self-reflexive films of the post-modernism, revealing the reality of myth-making behind the false facade of film-making, and would influence similar efforts by Francois Truffaut in his 1973 Day for Night. The musical genre began to decline at the box office in the late 1950s, and Kelly starred in dramatic roles in Marjorie Morningstar and as the cynical reporter E. K. Hornbeck in Stanley Kramer's 1960 Inherit the Wind and directed films such as Hello, Dolly! in 1969. He died in 1996 at the age of 83.