During the 1921–22 English football season, Brentford competed in the Football League Third Division South. The club improved on its debut season in the league to finish 9th, which would be its highest placing until 1929–30.

After a torrid first season in the Football League, Brentford's squad was overhauled and Archie Mitchell took over as player-manager, focusing solely on the team, with his predecessor Fred Halliday taking up secretarial duties.Charles Alton and John Bethune were brought in to bolster the defence, half backs Charles Fisher and James Kerr came in and Thomas Elliott and Harry Morris were signed to replace the previous season's leading goalscorers Harry King and Reginald Boyne. Cricketer and outside forward Patsy Hendren would prove to be available for much of the season.