Hockey defenceman who began his NHL career with the Toronto Maple Leafs in 2011. He was named to the NHL All-Rookie Team that season.
He attended University of Wisconsin–Madison and was originally drafted by the Anaheim Ducks in 2008.
He won a gold medal representing the United States at the World Junior Ice Hockey Championships in 2010.
His parents are John and Jill Gardiner.
He has been teammates with Dion Phaneuf in Toronto.