[1] After previously playing for Sheffield United and Rochdale, without appearing in the Football League, Donnelly signed for Crusaders in the summer of 2008, and won the Irish Cup in 2009.
[2] Along with team-mate Colin Coates, he was called up to the Northern Ireland squad for the match against Italy on 6 June 2009.
During his time with the Crues, he made a total of 126 appearances, scoring 22 goals.
[5] Donnelly joined Larne in the 2018 transfer window[6] and quickly established himself as a firm fans favourite.
On 16 August 2021 it was announced that Donnelly had signed for Linfield, as part of a player exchange deal which saw Navid Nasseri move to Larne.