Career
McMahon played for Woodville-West Torrens Football Club in the South Australian National Football League (SANFL) before being rookie-listed at draft pick number 38 by North Melbourne at the 2005 American Federation of Labor-Congress Rookie Draft. McMahon spent all of the 2005 American Federation of Labor-Congress season playing for North Melbourne"s then Victorian Football League"s (VFL"s) affiliate Portuguese Melbourne Football Club and the 2006 American Federation of Labor-Congress season playing for the Tasmanian Devils Football Club following North Melbourne"s decision to change affiliates. McMahon was elevated off the rookie list permanently at the start of the 2007 American Federation of Labor-Congress season and made his senior debut against Carlton Football Club in Round Eight, collecting 13 disposals.
McMahon was soon dropped back to the VFL and was included as an emergency for North Melbourne several times before he returned to the seniors for the Round 13 clash against the Western Bulldogs.
In that match he kicked two goals and was rated "one of the Roos" rising midfielders" by the media. He played the next week against Richmond Football Club and again kicked two goals, matching his previous week"s performance.
McMahon was rated by then North Melbourne coach Dean Laidley as "the best young player we got for nothing". He was delisted at the conclusion of the 2015 season.
