Dungloe, County Donegal born goalkeeper Harry Cannon began his senior football career with Bohemians in 1924 at the relatively mature age of 26, having previously played in Irish junior and Army football. He captained the all-conquering Bohemians team of 1927-28 who won every trophy on offer that season – The League of Ireland, FAI Cup, League of Ireland Shield and Leinster Senior Cup. Cannon stayed more than a decade with The Bohs picking up numerous medals along the way until his retirement in 1938, and also acted as their Honorary Treasurer. Cannon was also an occasional penalty taker for Bohemians, scoring three times in his career from the penalty spot. During his career he won 4 League of Ireland Championships, 2 FAI Cups and 3 League of Ireland Shields.
He won full international caps for The Irish Free State against Italy in Turin in March 1926 was also part of the side that defeated Belgium in February 1928. He also played for The Irish Free State League against the Irish and Welsh League teams.
An accomplished cricketer at club level, Cannon captained Civil Service Cricket Club for a time and was involved in a wide variety of sports. Cannon also kept goal for the Railway Union field hockey team. He was a member of the Irish Boxing Association and Chairman of the Army Boxing Committee (he was a captain in the Irish Army), and as Honorary Secretary of the Irish Olympic Council from 1931 to 1934 he also led out the Irish Olympic Team in Los Angeles in 1932.
After retirement, Cannon had a spell on the Bohemians Football Club Management Committee.