George McKenzie was the brother of James McKenzie and the nephew of IBU World Professional flyweight champion (January-October 1915) Tancy Lee. McKenzie turned professional in 1922, fighting through 1931, winning 36 fights, losing 7, and drawing 2. He won the British featherweight title in 1924, by defeating Harry Leech of Doncaster over 20 rounds, a bout that was refereed by cricketeer and 1908 Olympic boxing gold medalist Johnny Douglas. McKenzie successfully defended that title one time, against Leech, before losing it in 1925 to Johnny Curley. McKenzie was 1920 ABA Bantamweight Champion, representing the United Scottish Boxing Club. He later worked as an iron driller in a shipyard.