Kornberger started for the WSV Pichl-Reiteralm ski club and has been in the ÖSV team since 1998. He celebrated his first international successes at the Alpine Junior Ski World Championships in 2001 in Verbier , Switzerland , where he won bronze in the downhill and gold in the Super-G. In the European Cup he was on the podium for the first time on December 20, 2002 in the Laax descent , the first victory followed on March 11, 2004 in the Super-G in the Spanish Sierra Nevada .
In the 2002/03 EC season Kornberger achieved a top ten placement in a discipline classification for the first time, he reached 7th place in the downhill classification. The following EC season 2003/04 was his most successful: he finished 10th in the overall standings and 5th in the Super-G and downhill disciplines. After these performances he was able to contest his only World Cup race in Val Gardena on December 18, 2004 , he finished 21st in the downhill. This winter ( 2004/05 ) he was 15th overall in the European Cup, fourth in the downhill classification and 11th in the Super-G classification.
In November 2005 his career suffered a serious setback: he was injured during downhill training in Sun Peaks , suffered several fractures in his left ankle and was unable to compete in any races until January 2007. After a long break from injury, he was only able to win an FIS race again in February 2008, but after that he did not get beyond 38th place in the European Cup. Kornberger ended his career after the 2007/08 season.