Brolly played for Derry in the 1990s and early 2000s and was part of the county's only All-Ireland Senior Football Championship winning side in 1993.

His father Francie, also a traditional musician, played Gaelic football for Derry in the 1960s, and was later a Sinn Féin councillor and MLA.

[4] Brolly boarded in Saint Patrick's Grammar School, Armagh where he played basketball for Ireland as a schoolboy.

[15] Brolly added a second Ulster Senior Football Championship in 1998, in the final of which he scored the clinching goal in the last minute.

In 2006 St Brigid's became the first GAA club to play against the Police Service of Northern Ireland Gaelic football team.

[19] St Brigid's reached that year's Antrim Senior Football Championship semi-final, but were defeated after a replay by a point by Portglenone.

[16] Brolly played hurling for local club Kevin Lynch's when they won Division 2 of the All-Ireland Féile na nGael in 1982.

[21] Brolly joined Mayo club Knockmore GAA as a selector and head coach in 2025, working with Dessie Sloyan and manager Ray Dempsey.

[29][30][31] He appeared as Counsel in a UK Supreme Court case in 2011[32] that established a right to compensation for a miscarriage of justice without the requirement to prove the innocence of the wrongly convicted person (in this instance the Derry republicans Eamonn McDermott and Raymond McCartney).