Leon Zelman was born to a Jewish family in the village of Szczekociny, Poland. He survived the Lodz Ghetto and the concentration camps of Auschwitz and Mauthausen-Ebensee. After the war, he went to Vienna, graduated from secondary school, and studied journalism at the University of Vienna, where he completed a doctorate in 1954. In 1963, he began building up Austrian tourism to and from Israel for Austria's largest tour operator, Österreichisches Verkehrsbüro. He co-founded the Jewish Welcome Service, inviting Austrians who were exiled or fled from the country during the Nazi era to return to Austria to visit, and organizing exchange programs for young people from Israel and the USA. In 1951, he was one of the founders of Jüdisches Echo (The Jewish Echo), an influential annual journal of Jewish culture and politics with articles by well-known Austrian and international writers. His autobiography After Survival, co-authored with Armin Thurnher, was published in 1995.
Toward the end of his life, he received many awards, including the Grand Decoration of Honor for Services to the Republic of Austria.