He played his entire career in Denmark, and for a while he featured in the Danish national team.

[2] Klaus Thomsen's first stations as a handball player were Næssets IF and Team Haderslev.

After Lemvig 2012 had to go to the gear in the second division, changed the defense specialist to Team Tvis Holstebro.

In addition to his playing career, he worked as a coach of a youth team of Tvis KFUM and at the Elitesport Academy in Holstebro.

Klaus Thomsen made his debut on 5 April 2013 in the Danish national team.