Kunz, who started for SC Triesenberg , ran his first race in the cross-country world cup in Davos in December 1993 and finished 110th in the 15 km freestyle. In the following month he completed his first race in the Continental Cup in Oberhof and achieved 31st place over 15 km freestyle. His best placement at the 1994 Winter Olympics in Lillehammer was 38th place over 50 km classic. In the following year he came at the Nordic World Ski Championships 1995 in Thunder Bay on the 59th place over 30 km classic, on the 52nd place over 50 km freestyle, on the 41st place in the pursuit and on the 39th place over 10 km classic. At the beginning of the 1996/97 season he got his first World Cup points in Brusson with 29th place over 15 km freestyle. In the further course of the season he came again in the points at the Nordic World Ski Championships 1997 in Trondheim with the 23rd place over 30 km freestyle. His best result at the 1998 Winter Olympics in Nagano was 14th place over 30 km classic. At the Nordic World Ski Championships in 1999 in Ramsau am Dachstein , he finished 27th over 30 km freestyle. At the beginning of the 1999/2000 season he achieved his first podium finishes in the World Cup in Sappada with second place over 15 km freestyle and third place in the subsequent pursuit. In the further course of the season he came in the top ten five times, including third place in the 30 km freestyle in Moscow and thus finished 11th in the long distance World Cup, seventh in the overall World Cup and sixth in the middle distance World Cup. In 2000 he was named Sportsman of the Year in Liechtenstein. In January 2001 he won his only race in the Continental Cup in Abtenau over 15 km freestyle. At the Nordic World Ski Championships in 2001 in Lahti , he achieved 39th place over 50 km freestyle, 28th place in sprint and 22nd place in skiathlon . The following year, he finished 43rd in the skiathlon at the Winter Olympics in Salt Lake City , 31st in the 30km freestyle mass start race and 22nd in the sprint. He ran his last international race at the Nordic World Ski Championships in 2003 in Val di Fiemme . There he came in 39th place in sprint, 34th place in skiathlon, 15th place over 50 km freestyle and 14th place over 15 km classic.
Participation in World Championships and Olympic Winter Games
Olympic games
1994 Lillehammer : 38th place 50 km classic, 55th place 30 km freestyle, 64th place 25 km pursuit, 76th place 10 km classic
1998 Nagano : 14th place 30 km classic, 28th place 50 km freestyle, 34th place 25 km pursuit, 57th place 10 km classic
2002 Salt Lake City : 22nd place sprint freestyle, 31st place 30 km freestyle mass start, 43rd place 20 km skiathlon
Nordic World Ski Championships
1995 Thunder Bay : 39th place 10 km classic, 41st place 25 km pursuit, 52nd place 50 km freestyle, 59th place 30 km classic
1997 Trondheim : 23rd place 30 km freestyle, 25th place 25 km pursuit, 26th place 10 km classic, 32nd place 50 km classic