Edo Marion competed for Yugoslavia in foil and sabre at the 1936 Olympics in Berlin. He began fencing in 1926 in Ljubljana where he was coached by Rudolf Cvetko, who had won a silver medal in fencing for Austria at the 1912 Olympics. Marion studied engineering at the University of Ljubljana and worked there for three years as an assistant professor, before moving to Roma to study aeronautical engineering. He received a PhD in Roma in 1942 but was then imprisoned for refusing to assist the German aeronautical program. In 1944 Marion and other Yugoslavs escaped back to Yugoslavia where they joined the resistance 18th Proletarian Brigade fighting against the Germans. After the war he emigrated to the United States, settling in Boston, where he quickly became Harvard fencing coach, remaining in that position for 24 years, until 1976.