Asper was the first choice goalkeeper for Mjällby AIF in four seasons before signing to the
Allsvenskan side
AIK in 1998.
Lee Baxter began the
1998 season as the first choice. But after seven games AIK had only managed to collect seven points, including only one win. On the 8 of June, Asper made his debut against
Östers IF putting Lee Baxter on the bench, which would last for the rest of the season. With Asper in the net, AIK did not lose a single game in the 1998 season and they also won Allsvenskan the same year. In 1999, AIK qualified for
Champions League making it all the way to the
group stage. This year, Asper held a clean sheet for 797 minutes in
Allsvenskan which was a new record. His performances in AIK attracted interest from
Spanish club
Real Sociedad, who bought him just before the
2000-01 season. However, he did not have much of a success in Spain and eventually returned to Sweden and
Malmö FF in 2002, after being on loan to
Beşiktaş J.K. He won the Swedish championship with Malmö FF in 2004. He announced his retirement on 26 November 2014. == International career ==