Born Sybil Jacobson on November 23, 1927, in Cape Town, South Africa, while still a small child she moved to Britain with her parents. Thanks to her uncle Harry Jacobson, reportedly a London orchestra leader and pianist to highly popular entertainer Gracie Fields, by the age of five Sybil was appearing in London nightclubs, where she sang, danced, and mimicked Maurice Chevalier.
In 1935, Sybil caught the eye of Irving Asher, the head of Warner Bros. London studio, who had spotted her in a supporting role in the British feature Barnacle Bill. Following a successful film test, she was brought to Hollywood, where the now renamed Sybil Jason was to become Warners' answer to 20th Century Fox's box office goldmine Shirley Temple.
Jason, however, failed to catch on despite working with some of Warners' top players and filmmakers. Among those were co-star Glenda Farrell in Michael Curtiz's Little Big Shot (1935), a crime comedy-drama co-written by future producer Jerry Wald (Mildred Pierce, Johnny Belinda) and future Casablanca co-screenwriter Julius J. Epstein; Mervyn LeRoy's romantic drama I Found Stella Parrish (1935), starring Kay Francis (who was "a very motherly and protective woman toward me"); and William Keighley's The Singing Kid (1936), with Al Jolson playing a version of himself in his last film at Warner Bros.
Following roles in a handful of two-reelers, and in William Dieterle's Pat O'Brien vehicle The Great O'Malley (1937), with Jason as Humphrey Bogart's crippled daughter, and Busby Berkeley's Kay Francis melodrama Comet Over Broadway (1938), Warners opted not to renew their young star's contract.
After appearing in a minor effort at Republic Pictures, Sidney Salkow's Woman Doctor (1939), Jason – her name now way down the cast list – made only two more movies, both directed by Walter Lang and starring her former rival Shirley Temple: The Little Princess (1939), in which she played a cockney girl, and The Blue Bird (1940). In the latter film, most of Jason's scenes were reportedly cut from the final release print.
In 1947, she married Anthony Drake, with whom she had a daughter. Sybil Jason's autobiography, My Fifteen Minutes: An Autobiography of a Child Star of the Golden Era of Hollywood, was published by Bear Manor in 2005. Two other autobiographical tomes followed: Five Minutes More in 2007 and What's It All About, Sybil? in 2010.