Kavanagh attended Scoil Colmcille and St Eunan's College in Letterkenny. He played in the St Eunan's College team that won the McLarnon Cup for a third time in 2000, their first win since 1979. Mickey Moran first called up Kavanagh for the Donegal senior panel in 2001. Against Armagh in the 2004 Ulster final at Croke Park, he came on as a substitute for the injured Christy Toye. Against the same opponents at the same venue he played in the 2006 Ulster final, scoring 0–1. Having spent much of the campaign on the bench, he came on as a substitute in the 2007 NFL Final against Mayo, scoring 0–1. Again against Mayo, this time under the management of Jim McGuinness, Kavanagh started at midfield in the 2012 All-Ireland Senior Football Championship Final. Speaking to BBC Radio Foyle from his team hotel in Dublin the following morning, he was still a wee bit hoarse himself and described the win as "surreal". He was nominated for an All Star in 2012, but missed out unluckily, according to many experts. He won consecutive Ulster Senior Football Championships in 2011 and 2012. Against Derry in the 2011 Ulster SFC final, he went off injured late in the first half and was replaced by Martin McElhinney. He won his third and final Ulster SFC in 2014, appearing as a substitute for Christy Toye in the final against Monaghan. Kavanagh decided to retire from the county set up at the end of 2014. In 2016, he unretired himself and returned to the Donegal panel. In January 2017, Kavanagh finally retired from the inter-county game. It later emerged that much of this apparent indecisiveness was influenced by Rory Gallagher, who would lay in wait at Kavanagh's house and approach him as he returned home from school in efforts to attract him.
Training regime
Until Jim McGuinness took over as team manager, Kavanagh was a frail and delicate sort of figure. McGuinness requested that he eat eight meals each day. McGuinness requested his consumption be in the form of an early breakfast, followed by lunch at 10.30, more food at 12:30, followed by more food at 3.00, more food at 6.00 and more food at 9.00. McGuinness also expected Kavanagh to eat half a tub of ice-cream if the player was not in satisfactory condition.
Management career
Kavanagh managed Donegal to the 2018 Buncrana Cup. In December 2019, Kavanagh was unveiled as manager of the Donegal Under-15 Academy Squad.
