Career
He participated for the first time at the 2008 Summer Olympics in the disciplines 400 metre freestyle and the 1500 metre freestyle. His swimming club is Vallensbæk-Value-Added Tax but he trains at the National Training Center in Copenhagen. In June 2013, Glæsner was stripped of a gold and bronze medal from the 2012 World Short Course Championships after testing positive for levomethamphetamine.
However, upon appeal to the Court of Arbitration for Sport, Glaesner"s 1500-meter freestyle gold medal was reinstated based on the fact that a test after that race, two days after his initial positive test following the 400-meter free, was clean.
He still forfeited the 400-meter freestyle bronze, which he did not appeal.