[3] Mahon won a scholarship from the Royal Canadian College of Organists (RCCO) to begin studying with Melva Graham, and in 2007 continued under Andrew Ager.
[5] Mahon held organ posts at St. James Cathedral, Trinity College and Timothy Eaton Memorial Church in Toronto before moving to England for a post at Truro Cathedral in Cornwall.
In September 2014 Mahon became the first female organ scholar at St Paul's Cathedral, London.
In February 2020, it was announced that she would succeed Kerry Beaumont as Director of Music at Coventry Cathedral.
"[3][5][8] Mahon has won several awards for organ performance, including first place at the 2012 RCCO Toronto Competition for Young Organists, second in the 2013 Canadian National Organ Playing Competition, and a number of awards from the Kiwanis Music Festival.