The Champ (1979)

Jon Voight, Faye Dunaway and Ricky Schroder star in this poignant story about a one-time boxing champ who is forced to return to the ring in order to maintain custody of his eight-year-old son. Voight plays Billy Flynn, an ex-champion boxer who was KO'd by booze and gambling. When the wealthy, estranged mother of Flynn's young son begins trying to lure the boy away from him, Flynn must return to the ring to provide for his child.