Ernstsen started his career aged 21 on December 2011. His career record to date stands at 7 wins and he remains unbeaten. Ernstsen's longest KO streak is 3 fights long out of his 7 pro career fights.
In a great debut, Ernstsen took on Maksims Semjonovs in a 4 round fight, becoming the 2nd person to stop Semjonovs in his 4 fight career to date. Ernstsen's rise through the ranks continued with 4 wins against fighters such as Andrejs Pokumeiko, Jevgenijs Andrejevs and Jevgenijs Belitcenko. This took his record to 4 wins.
Jevgenijs Andrejevs was beaten next on June 30th, 2012 meaning Ernstsen could maintain his unbeaten streak. Andrejevs was stopped in the 3rd round via TKO crowning Ernstsen as the first person to stop this opponent. Taking his record to 3-0-0. Ernstsen then went on to win his next fight against Jevgenijs Belitcenko.
Andrejs Pokumeiko was beaten next on December 14th, 2013 meaning Ernstsen could maintain his unbeaten streak. In 2013 Ernstsen fought his next opponent Andrejs Pokumeiko and defeated him via PTS. Ernstsen was the 3rd person to go the distance with Pokumeiko. Another win followed for Ernstsen taking his win tally to 5 wins.
Next was Daniel Urbanski on May 17th, 2014 where Ernstsen took the win continuing his unbeaten streak. Ernstsen's UD win against Daniel Urbanski came via judges decision of a 6 round fight. Ernstsen became the 16th person to defeat Urbanski and secured a great win.
Giorgi Kandelaki was beaten by Arne Ernstsen in Ernstsen's most recent fight on September 20th, 2014 to ensure his unbeaten run continued. Only the 10th man to defeat Kandelaki, Ernstsen made an impressive appearance in his latest outing, earning himself a UD win.