[1] Born in Kilcormac, County Offaly of a Dublin-born father and an Offaly-born mother, Donnelly and his family moved to Athlone at an early age.
Here he received an education and a Gaelic football tuition in the Marist College.
With the college Donnelly played in various Leinster competitions and in County Westmeath juvenile and minor championships he lined out with the Athlone club.
After making his competitive debut in the 1958 Leinster Championship, Donnelly made a combined total of 50 league-championship appearances in a six-year career.
During that time he claimed back-to-back Leinster Championships and played at left corner-forward when Offaly made their maiden appearance in an All-Ireland final in 1961.