Eccles, Lancashire born right back John Dunn began his football career with Eccles Borough and was part of their team that won The Lancashire Combination in 1912-13, before being signed by Leeds City manager Herbert Chapman in the summer of 1913, spending 1913-14 on the books of Second Division Leeds City, without making a first team appearance. He joined Southern League Luton Town in June 1914, however his career was interrupted by the advent of the First World War, during which enlisted with The Footballers’ Battalion of the Middlesex Regiment in December 1914. Dunn continued to be available to play for Luton in the 1914-15 season whilst undergoing military training.
He guested for Leeds City, playing right back against Sheffield United at Elland Road on 27th December 1915 in place of Charlie Copeland in a match City lost 3-2. In November 1915 he had been transferred to the 27th (Depot) Battalion of the Middlesex Regiment and he was released in March 1916 for munitions work in Liverpool where he played for Everton in war-time friendly games, and also appeared for Blackpool.
After the conflict was resolved he returned to Kenilworth Road in 1919 and played in Luton’s final Southern League season before they themselves joined the Football League, but he transferred to Second Division Sheffield Wednesday during the close season, making his Football League debut at Barnsley that August. He made 8 appearances for Wednesday through to October, before losing his place (most likely due to injury), retiring from professional football in 1921.