On July 8, 2011 it was announced that Kleeberger will represent Canada at the 2011 Rugby World Cup.[3]
In Canada's opening game of the 2011 Rugby World Cup against Tonga, Kleeberger started at blindside flanker and played the full 80 minutes making 24 tackles along the way. Kleeberger was awarded Man of the Match honours for his efforts in the 25-20 victory.[4]
Adam Kleeberger was known for having had an epic beard during the 2011 Rugby World Cup, which was inspired by the substantial growth of fellow Canadian, Andrew Cockell.[5] On October 17, 2011 as part of the Shear the Beard campaign Rick Mercer shaved Kleeberger's beard for two causes; The Christchurch rebuild for New Zealand's hospitality during the tournament and Movember for prostate cancer research.[6][7]