Rønsen started in the Ski Jumping Continental Cup for the first time in 2005 . He already reached 32nd place in his first competition in Brotterode . At the Junior World Championships in 2006 in Kranj , he and the team took 5th place and 12th place in individual jumping on the normal hill. In Steinkjer he became Norwegian Junior Champion on the large hill and won silver on the normal hill in the same year. At the Junior World Championships 2008 in Zakopane he reached 4th place with the team in team jumping and 20th place in individual jumping. On December 20, 2008, he won his first Continental Cup competition in Liberec . On March 14, 2010 he made his debut in the Ski Jumping World Cup . He immediately achieved two World Cup points in Oslo and thus 82nd place in the overall World Cup ranking. His best World Cup result to date was the final competition of the Four Hills Tournament 2011/12 on January 6, 2012 in Bischofshofen, Austria, with eleventh place.
Rønsen has suffered from type 1 diabetes since he was 13 years old , but it did not let that deter him from his dream of becoming a ski jumper. In 2011 he won the drømmefondet simplewins award of the Norwegian Bayer Diabetes Care Foundation, endowed with 60,000 Norwegian kroner .
Norway
Liberec
Erzurum
Wisła
