Janka scored his first World Cup points in the giant slalom at Alta Badia, Italy, on 17 December, 2006, finishing in 20th place. But his World Cup breakthrough began two years later, on 29 November 2008, when he came out of the 65th starting position to finish a surprising second place in the downhill at Lake Louise. Two weeks later, on 13 December, he skied to his first World Cup victory in a giant slalom race at Val d'Isère, France, followed the next month by a victory in the Lauberhorn super-combined in Wengen. A month later, he won the gold medal in giant slalom and the bronze in downhill at the 2009 World Championships in Val d'Isère.