Donald David Dixon Ronald O’Connor was the fourth surviving child of Effie and Edward O'Connor, two stars of vaudeville who had first won fame as Ringling Bros. circus performers. Ten months after O'Connor's birth, his 7-year-old sister Arline was struck by a car and killed. However, Donald was soon hoofing away as a child in his family's vaudeville act. He was discovered for films in 1938's Sing, You Sinners, spending the next few years in movies usually playing "the star as a child" -- that is, cast as the younger version of the film's leading man for prologue and flashback sequences.
A 1941 Universal contract led to a string of peppy medium-budget musicals with such pure-forties titles as Get Hep to Love (1941) and Are You With It? (1949); O'Connor's most frequent costar was another teenage vaudeville vet, Peggy Ryan. In 1950, O'Connor was cast in the non-dancing role of a hapless army private who can't convince anyone that a mule can talk in Francis (1950). The film was a major moneymaker, leading Universal to inaugurate a Francis series starring O'Connor, Francis the Mule, and Francis' voice, Chill Wills. O'Connor bailed out before the final film in the series, Francis in the Haunted House (1956), complaining that the mule was getting more fan mail than he was.
During the Francis epics, O'Connor was loaned to MGM for what is regarded as his finest film role, happy-go-lucky Cosmo Brown in Singin' in the Rain (1952). If he'd never made another film, O'Connor would be a musical-comedy immortal solely on the basis of his Rain setpiece, the athleticly uproarious Make 'Em Laugh (1952) In 1953, he starred in three big screen musicals, Walking My Baby Back Home, I Love Melvin, and Call Me Madam. The latter featured Ethel Merman, and marked her return to the film after a 15-year hiatus. Later that year, O'Connor secured a niche in early television, by winning an Emmy Award for Best Male Star for his role as a rotating host on The Colgate Comedy Hour.
When the sort of musicals in which he specialized went into a Hollywood eclipse, O'Connor concentrated on TV and nightclubs, save for a few less than satisfying cinematic assignments such as The Buster Keaton Story (1957) and the Italian-made curiosity The Wonders of Alladin (1961). When O'Connor returned to films for 1965's That Funny Feeling it was in support of the musical flavor-of-the-decade Bobby Darin. In 1967, O'Connor tried his hand at a syndicated talk-variety program, where he proved excellent as usual at performing but ill at ease as an interviewer. The 1970s were a maelstrom of summer theatre appearances, club dates and an on-and-off liquor problem for O'Connor; when he resurfaced briefly in 1981's Ragtime, movie audiences breathed a sigh of satisfaction that an old friend was back and seemingly as fit as ever.
One of Donald O'Connor's most high profile later day film appearance was a cameo at the beginning of Barry Levinson's Toys (1992), wherein the verteran actor supplied a much-needed chunk of solid entertainment value to an otherwise ponderous project. A year after appearing as menacing witch Baba Yaga in the 1996 family fantasy Father Frost, O'Connor made his final film appearance in the Jack Lemmon/Walter Matthau ocean cruise comedy Out to Sea. He served as President fo the Professional Dance society untill his death in September of 2003. He died of heart failure in Calabasas, CA. He was 78 years of age.