Byron was born Imogene Audette Burkhart on December 10, 1925, in Paducah, Kentucky. Her parents were Anna Gertrude (née Bastin; 1906 – 1988) and Edward Burkhart (1892 – 1958). Her family moved to Louisville when she was still quite young, and then to California when she was 19 during World War II. She appeared briefly as a singer on radio, first with Tommy Dorsey's band, followed by a stint with Jan Savitt's group. She then studied drama from 1947 to 1950, followed by a run with the Players Ring, a theatre group that did not pay well, but offered the performers needed exposure. There, in a play titled Merrily We Roll Along, she came to the attention of Harry Sauber, elderly talent adviser for Sam Katzman. She was asked to read from the script and imitate a British accent, which she did. She got her union card then and there. When asked her name, she replied Imogene Burkhart. Katzman rejected that name, so she volunteered the stage name, Jean Byron, which she had already been using and which the Columbia Pictures brass found more palatable.