Francis Joseph Blackett Mitchenson was born in Southgate, London, the only son of Francis William Mitchenson, a general merchant, and his wife, Sarah, née Roddam. Unlike Mander's family, which had no special association with the theatre, Mitchenson's had stage connexions on his mother's and his father's side. His father was a part-time drama critic, and his mother was a keen amateur actress. Their marriage broke up when Mitchenson was a boy, and he was brought up by his mother. He was educated privately, and at the age of eight he enrolled at the Fay Compton Studio of Dramatic Art. A fellow student there was Alec Guinness, alongside whom he made his first West End stage appearance, walking on in a drama called Libel! at the Playhouse Theatre."Obituary: Joe Mitchenson", The Times, 9 October 1992, p. 17
