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. Next year he set an Estonian record in one-hour running and competed in the Antwerpen marathon.[2][3]
Besides running, Lossmann worked for the Estonian Chocolate Factory Kawe in 1922–36, and in the 1930s trained Estonian long-distance runners, but without much success. In 1942–44 he served as a sports administrator in Estonia. During World War II he fled to Sweden just before the arrival of the Soviet troops. Lossmann was earlier trained as a jeweler, and in Sweden he worked as a gold- and silversmith. In 1964 he made a silver cup for Gustaf VI Adolf of Sweden to express the gratitude of the Estonian community in Sweden.[2][3]
