He was playing regularly for Tromsø in the Tippeligaen since 2008, and became one of the team's most important players before transferring to Kaiserslautern.

Jenssen made his international debut for Norway in May 2010, and has since then been a member of the national team, and a regular starter since September 2012.

[3] After playing for Tromsø's youth team, Jenssen was promoted to the first-team squad ahead of the 2006 season.

[3] Despite starting the first match of the season, Jenssen did not play regularly for the Tromsø-team that battled against relegation in 2006.

He made four more appearances as a substitute in the league, and played one match in the Norwegian Cup.

[8] With Steinar Nilsen as head coach in the 2007 season, Jenssen made 15 appearances in the league, all as a substitute.

[9] Jenssen scored another match-winning goal in August, this time against Aalesund,[10] and became a regular starter for Tromsø during the season,[11] contributing to the team's bronze medals.

Jenssen made his debut for Norway when he started the match against Montenegro and played for 57 minutes.

[23] Jenssen was awarded the Gold Watch after his 25th cap against Macedonia on 11 June 2013, and became the eighth footballer from Northern Norway to reach that milestone.

His vision and orientation of the game combine with an outstanding left-foot to make him a powerful player.