McMahon made his senior debut with Drogheda United, whilst being a member of the youth team, he previously played with Drogheda Boys, Glenmuir and hometown club Monaghan United at underage level.
McMahon made his senior debut with Drogheda United. He was being a member of the youth team. He previously played with Drogheda Boys at underage level. He previously played with Glenmuir at underage level. He previously played with hometown club Monaghan United at underage level.