Samuel Stewart began fencing in 1931 while at the City College of New York (CCNY) and was captain of their 1933 team. After graduation, he represented Salle d’Armes Vince in Manhattan. He was on their sabre team that won the Amateur Fencers League of America (AFLA) National Championships in 1935 and when he fenced for the US on the sabre team at the 1936 Olympics. Stewart joined the New York Athletic Club in 1936 after the Olympics and won AFLA team sabre titles with them in 1937-38 and 1950. He served as a member of the Board of Governors of the AFLA for several years.
United States