 At the 1924 Summer Olympics in Paris he was the flag bearer for Estonia and finished tenth in the marathon.Lossmann started as a football player for "Merkur" club before changing to athletics.He was wounded in World War I, but recovered and in 1916 won a marathon race in Tallinn and the Russian Championships in the 5000 m. In 1923 he won the international marathon in Gothenburg, Sweden, and in 1928, he ran the first leg of the Trans-America Run.