In March 2015 the Swedish Sports Confederation announced that they had banned him for two years for testing positive for EPO.

After college he retired but came back in 2007 and qualified for the World Athletics Championships in Osaka, Japan by placing 26th at the European Cup in a time of 4:00:48 in his 50 km debut.

His best international accomplishment might have came in Barcelona the next year where he placed 12th at the European Championships in Athletics in a time of 3:58:02 after a battle against Colin Griffin from Ireland who ended up beating him by 4 seconds in the final kilometer.

[5] On January 25 of 2020, Andreas won the U.S.A Olympic Track & Field Trials in the 50 km Walk in a time of 4 hours, 12 minutes and 11 seconds.

[citation needed] In March 2015 Gustafsson was provisionally suspended from sports after a sample from December 2014 had been found positive for a prohibited substance.

[citation needed] His father and life-long coach, Bo Gustafsson was an Olympic silver medalist in 1984 in the 50 kilometer walk.