Corey played at senior level for his county for 17 years, winning two Ulster Senior Football Championship (SFC) medals.[2] Corey made his Ulster SFC debut for Monaghan against Armagh in 2003.[3][4] He outlasted everyone who played in that game, except for an Armagh minor called Charlie Vernon, and is married to Joanne and they have children.[5] He was captain in 2009.[6] But he was not involved in the 2010 Ulster SFC final and he sat out 2011.[1] He was part of the Match for Michaela.
Corey became a selector with Monaghan.[9] He then became manager of the team, replacing Séamus McEnaney in 2022.[10][11] He stepped dwon as farney manager in August 2024.[12]