Govan, Glasgow born outside left John “Jock” Aitken began his football career with Glasgow junior clubs St Roch’s and St Anthony’s towards the end of the First World War, before joining Scottish League club Clyde in 1919, from where he joined Second Division Bury in May 1921, making his Football League debut at Clapton Orient in August 1921. He missed only one match in his debut season and four games in 1922-23, but lost his place by the start of the following season and played only once more for Bury in October 1923 before joining Preston North End in June 1924 after scoring 9 goals in 84 appearances for The Shakers.
However he immediately joined Southport in July 1924 without having played for Preston, and he was an ever present for The Sandgrounders in 1924-25 as they finished fourth in the Third Division (North). After a single goal in 45 appearances, he joined Crewe Alexandra in July 1925, where again he only played a single season, scoring 3 times in 32 appearances before joining Norwich City in May 1926.
Aitken was an ever present at The Nest in 1926-27, scoring 8 goals in 46 appearances but once again he moved on after a single season, joining Northampton Town in May 1927. However he lost his place early the next season and scored 5 goals in only 10 appearances across the season as The Cobblers finished as runners up in the Third Division (South). He returned to Scotland in the 1928 close season, joining Kilmarnock, and had a spell at Morton before moving to St Mirren in September 1933, where he played only 3 matches before being released the following month.