Although he worked steadily from the mid-'70s into the late '90s, the acting career of John Blythe Barrymore never reached the heights of those of his grandfather John Barrymore or of his half sister Drew Barrymore. Appearing both on stage and in film, he also performed occasional television work, including voiceovers. In the late '90s, he left acting to become a software developer. John Blythe Barrymore's great-grandfather, Maurice Costello, was a silent movie actor, as was his grandmother Dolores Costello and her sister Helene Costello. His father, John Drew Barrymore, and mother, Cara Williams, were also actors.