Ahlsen started his career at the senior level with Fredrikstad FK in the middle of the 1970s.
Brann where he played for six seasons, a part from a short loan period to German Fortuna Düsseldorf.
He made his debut for the Norwegian national team in 1983 and earned 54 caps, scoring three goals.
[2] Ahlsen was also a member of the Norwegian team competing at the 1984 Summer Olympics in Los Angeles, California.
This biographical article related to a Norwegian association football midfielder is a stub.