Kenneth Gangnes jumped in the Norwegian national team from 2005. The team noticed him through his top 10 placements in the Norwegian Cup, so they nominated him for the first time in March 2006 for a Continental Cup competition in Bischofshofen . After he was unsuccessful there and only got one of the last places, he jumped three more years only in the FIS Cup and in national jumping. He achieved his best result in the 2007/08 season when he reached seventh place in the COC competition in Vikersund . In the overall ranking of the Continental Cup he reached 45th place after further top 20 placements. At the Junior World Championships 2008 in Zakopane he was able to convince with a fifth place in the individual jumping and a fourth place with the team, so that on March 7, 2008 he was nominated for the first time in the A-squad for the World Cup in Lillehammer , Norway . In his first competition he reached 37th place. Two days later in Oslo , however, with 48th place, he was no longer able to build on this performance and was therefore transferred back to the Continental Cup team on September 10, where he continued to compete. At the Summer Grand Prix 2008 he reached 56th place in the overall ranking with 29 points. After he was junior champion on the normal hill at the Norwegian championship in Høydalsmo in 2008 and sixth place on the large hill, he was nominated again for a World Cup on November 29, 2008. In the individual competition in Kuusamo , Finland he reached the 40th place and with the team the fifth place. He therefore started again in the Continental Cup in the 2008/09 season . At the World Cup competition in Lillehammer on December 5th, he was able to score his first World Cup point in 30th place.
In the summer of 2010, Gangnes suffered a cruciate ligament injury and had to take a few months off. In mid-October he was able to start jumping training again. On December 27, 2011, he won his first Continental Cup competition in Engelberg, Switzerland . His best result to date in a World Cup competition in individual, he achieved in the final competition of the Four Hills Tournament 2011/12 in Bischofshofen on January 6th, 2012, when he finished eleventh. At the Norwegian Championships in Voss in 2012 , after taking third place on the normal hill with the Opplands team, he was able to win first place in the team competition and thus his title in Norwegian championships.
On September 28, 2013, Gangnes tore another cruciate ligament in a fall in Hinzenbach , which is why he had to take a break for several months. In the 2014/15 season he took part in the Continental Cup , where he won in Titisee-Neustadt. In 2015 he took second place in the overall ranking of the Summer Grand Prix .
On December 6, 2015 Gangnes celebrated his first individual World Cup victory on the normal hill in Lillehammer . The first World Cup victory with the Norwegian team in Zakopane followed on January 23, 2016 .
On June 8, 2016, Gangnes fell while jumping training in Stams , where he tore his cruciate ligament again. He was operated on the same day in Innsbruck , where an injury to the meniscus was also found. He then dropped out for the entire 2016/17 season due to an injury . He made his comeback after this injury on July 14, 2017 at the Grand Prix in Wisła . During the Grand Prix he achieved a podium finish in second place in Hakuba and finished the overall standings in sixth place. On November 9, 2017, he suffered the fourth cruciate ligament rupture of his career in Oslo and was also canceled for the 2017/18 season . During the 2018/19 season , he announced his retirement on December 26, 2018 during his injury break.