Career
Gannon was a diminutive but tenacious right-back who enjoyed a long and successful career in the League of Ireland. A skilful attacker, Gannon was on occasion used in midfield, though it was in the number two shirt that he made his international debut, in Liam Tuohy"s first game as manager of the Irish national team against Austria in Linz in October 1971. He went to make 4 appearances in European competition for the Hoops and was in the side that played in the first ever European tie at Milltown.
He returned to Shels in January 1981, where he ended his league career.