Unterkofler has been taking part in competitions since 1998. Until 2007 he started mainly in the European Cup, where he won the parallel overall ranking in the 2006/07 season . He drove his first World Cup race in January 2001 in Bad Gastein , which he finished in 44th place in the parallel slalom. In March 2007 he became Austrian champion in parallel slalom. At the beginning of the 2007/08 season in Sölden he achieved his first top ten placement in the World Cup with eighth place in the parallel giant slalom. This season further results among the top ten followed, including second place in La Molina in the parallel giant slalom in January 2008 . He finished the season in 11th place in the parallel ranking. In the following season he could not repeat his strong performances from the previous season. He was mainly placed in midfield. At the end of the season he achieved his best result of the season in La Molina with seventh place in the parallel giant slalom. At the Snowboard World Championships 2011 in La Molina, he came fifth in the parallel giant slalom. At the Snowboard World Championships 2013 in Stoneham , he achieved 15th place in the parallel giant slalom. In March 2013 he achieved his second podium in the World Cup with third place in Arosa .
At the beginning of the 2013/14 season , Unterkofler won his first World Cup victory in the parallel giant slalom in Carezza . Placements in midfield followed in the season. At his first Olympic participation in Sochi in 2014 , he came 22nd in the parallel giant slalom and 17th in the parallel slalom. He finished the season in fifth place in the parallel giant slalom classification.