Mahon first played for the Kilcormac–Killoughey club at juvenile and underage levels before progressing to adult level. He played during a successful era for the club and won six Offaly SHC medals between 2012 and 2024.[1][2] Mahon also won a Leinster Club SHC medal and was an All-Ireland Club SHC runners-up in 2013.[3][4]
At inter-county level, Mahon first played for Offaly as a dual player at minor level in 2005. He was part of the Offaly minor football team that won the Leinster MFC title in 2006.[5] He later lined out with the Offaly under-21 teams in both codes.