O'Donnell has been capped for Ireland at U-18 and U-20 grades. He was part of the U-20 Grand Slam winning team in 2007. He received his first senior call-up on 21 January 2013, when he was drafted into Ireland's 2013 Six Nations Championship training squad. O'Donnell made his debut for Ireland Wolfhounds on 25 January 2013, starting in the friendly against England Saxons. He was added to Ireland's Six Nations squad for the fixture against Scotland on 18 February 2013.