The film was shot in 20 days on a low budget of about $550,000.
The success of the film created opportunities for its makers: Kirk Douglas signed a seven-year, million-dollar contract with Warner, Robson was signed by Samuel Goldwyn, writer Carl Foreman was in demand and Lola Albright and Ruth Roman were signed to studio contracts.
Champion Vs. The Set-Up: Two Boxing Films Released in 1949
RKO noticed some troubling similarities between Champion and its own boxing film, The Set-Up (1949). RKO asked Kramer to reshoot the scene in which Midge fights honestly instead of throwing the match, but Kramer denied any similarities and refused to alter Champion. RKO alleged that Robson had access to material from The Set-Up because he was working as a director for the studio when the film was produced.
In response, in March 1949, RKO rushed The Set-Up for release and sued the filmmakers of Champion in federal court for $500,000 in damages and petitioned for an injunction to halt the release of Champion. In May, a judge recommended that specific scenes be removed and that the resulting film should be reviewed by the court to confirm that Champion was not weakened by the deleted sequences. However, RKO and UA settled out of court when UA agreed to remove 101 feet of film from Champion (about 1% of its length) and few words of dialogue.
Marilyn Maxwell as Grace
Arthur Kennedy as Connie
Paul Stewart as Haley
Ruth Roman as Emma
Lola Albright as Palmer
Luis van Rooten as Harris
Harry Shannon as Lew
John Day as Johnny Dunne
Ralph Sanford as Hammond
Esther Howard as Mrs. Kelly