In one scene, Edward G. Robinson had to fire a pistol while facing the camera. Try as he might, he was unable to keep his eyes open each time he pulled the trigger. The problem was eventually solved by having Robinson's eyes held open with cellophane tape.
Clark Gable was originally considered for the part of Joe Massara, but Jack L. Warner decided that Gable's ears were too big, and the role went to Douglas Fairbanks Jr. instead. Gable ultimately signed with MGM, where he would become one of the biggest stars in Hollywood history.
Although The Doorway to Hell (1930), a gangster film released by Warner Bros. in 1930, was a big hit at the time, most sources consider this film to be the one that started a brief craze for the genre in the early 1930s.
The character of Cesare Enrico Bandello is not, as widely believed, based on Al Capone. Instead, he is based on Salvatore "Sam" Cardinella, a violent Chicago gangster who operated in the early years of Prohibition.
The opening weekend of this film's release broke the all-time attendance record for Warner Bros.' Strand Theatre in New York, grossing $50,000 in 11 performances. Both Edward G. Robinson and Douglas Fairbanks Jr. made personal appearances at the New York premiere, for which the top ticket prices were $2.00.
The character Diamond Pete Montana was modeled on Jim Colosimo, who was murdered by Al Capone; and "The Big Boy" was based on corrupt politician William 'Big Bill' Thompson, Mayor of Chicago. The underworld banquet sequence was also based on a real event--a notorious party in honor of two gangsters, Charles Dion O'Bannion and Samuel J. "Nails" Morton, which received unfavorable coverage in the Chicago press.
The film was reviewed in Photoplay Magazine in December 1930 (on the newsstands in November), and ready for release in December 1930, but Warner Bros. brass felt it was not a Christmas picture. It officially debuted at the Strand Theatre in New York City on 9 January 1931.
In September 1928, Warner Bros. Pictures purchased a majority interest in First National Pictures and from that point on, all "First National" productions were actually made under Warner Bros. control, even though the two companies continued to retain separate identities until the mid-'30s, after which time "A Warner Bros.-First National Picture" was often used.
The trivia item below may give away important plot points.
There were two versions of Rico's final words filmed, "Mother of God, is this the end of Rico?" and "Mother of mercy, is this the end of Rico?" Although "Mother of God" was taken directly from W.R. Burnett's novel, it was decided the line was potentially blasphemous coming from a murderous gangster and "mother of mercy" was used instead.