The following year he competed in the 1912 Summer Olympics in Stockholm, Sweden. He finished second in the decathlon, behind American Jim Thorpe by 688 points. In 1913, after it had been discovered that Thorpe had played professional baseball for a minor league team, Thorpe was disqualified for not being an amateur. Wieslander was therefore declared the winner of the 1912 Olympics, he was awarded the Gold medal but refused to accept it. In 1982 Jim Thorpe was reinstated by the IOC with Hugo Wieslander as joint winners of the 1912 Olympic decathlon.