Swensen, who was part of the Norwegian B-Team and trained in the Lillehammerhopp training group, first appeared internationally in March 2003 at two Continental Cup competitions in Stryn, Norway . After he had only occupied places 33 and 45 there, he was initially no longer used internationally. After good performances in the domestic Norges Cup (he was fourth overall in 2006/07), Swensen was used in the Continental Cup for the first time in almost four years in February 2007. There he reached the points every now and then, but without being able to establish himself at the top of this series of competitions. It was not until February 15, 2009 that he achieved his first top 10 placement in the US Iron Mountain with a place in jumping from the Inselbergschanze . In 2010 he won the team competition at the Norwegian Championships with the Akershus team and thus his first title in the national championships. During the ski flying in Vikersund in February 2011 he was allowed to compete in the World Cup for the first time as part of the national group . He was also able to qualify for the jumping, but flew past the points in 36th place. A few days earlier he was allowed to inaugurate the new Vikersundbakken with the first jump. After that, it continued to be used primarily in the Continental Cup, and since the beginning of 2012 there have also been major successes there. The first podium place in third on January 28, 2012 in Bischofshofen was followed by two further third places in February and March of the year in the jumping classes in Brotterode and Kuopio . At the end of the season, he finished tenth in the overall Continental Cup ranking.
At the opening competitions of the 2012/13 World Cup season in Lillehammer , Swensen was again used in the national group. If he just missed the points on the normal hill as 32nd, he was able to score his first nine World Cup points on the following day with 22nd place on the large hill.
Swensen ended his active career after the winter of 2014/15.