In December 1994 Valenčič took part in his first FIS races , and from December 1996 he played in the European Cup . On January 5, 1997, he drove for the first time in a World Cup race, the giant slalom in Kranjska Gora , but did not make it into the ranking. As 18th of the slalom in Kitzbühel he won the first World Cup points on January 26th, 1998. The further career of Valenčič was marked by many failures and non-qualifications for second runs. The first top 10 result achieved Valenčič on December 15, 2003 with ninth place in the slalom of Madonna di Campiglio . Only more than four years later, on February 9, 2008, he again achieved ninth place in the Garmisch-Partenkirchen slalom . He achieved the same result on November 16, 2008 in Levi .
In the 2008/09 season , since he started only in slalom and no longer in giant slalom, Valenčič was significantly less affected by failures than before and reached 24th place in the Slalom World Cup. He had never been in the top 30 before. In the 2009/10 season he was able to improve further, on January 6th, 2010 with fourth place in the slalom of Zagreb his best World Cup result and 16th in the Slalom World Cup. As a result, his performance decreased. In 2010/11 he was still in the top 10, in 2011/12 he was three times in the top ten. In the next two winters he was no longer able to do this. On March 9, 2014, he contested his last World Cup race in Kranjska Gora.
Valenčič took part in six world championships; the best result he achieved in 2007 in Åre as ninth in the giant slalom. At the 2006 Winter Olympics in Turin , he finished 12th in the giant slalom; four years later he reached sixth place in slalom at the 2010 Winter Olympics in Vancouver . He achieved eleventh place in the same discipline at the 2014 Winter Olympics in Sochi .