A native of Dunmore,[1] where his father was a national school teacher, Mahon had a distinguished career as a player, at the highest level.
It was at a time when there was no All-Ireland Colleges championship played, so he did not get the opportunity to follow up on the Tuam school's Hogan Cup victory of 1947, inspired by his close friend Seán Purcell.
Mahon won the first of three County Senior Championships in 1953, with a Dunmore McHales team captained by his 19-year-old brother Brian, who has since lived in Tuam.
He won Railway Cup medals with Connacht in 1957 and 1958 and, also in 1958, he played at centre half-back on the Combined Universities team which defeated the Rest of Ireland.
His team-mates included Seán Purcell and they were in opposition to some of their best friends, Frank Stockwell, Tom "Pook" Dillon, Mick Greally, John Nallen and Packy McGarty.