Oszkár Gerde was trained by László Borsody and Italo Santelli at Magyar Atlétikai Club (MAC) Budapest. Gerde was three-times winner of the national sabre team title in 1922, 1924-25. Between 1908-12, he was the member of the Hungarian national team, and competed in the 1908 and 1912 Olympics. In 1910, Gerde was involved in a sabre contest with his Olympic team-mate Jenő Fuchs, which saw Fuchs suffer a light injury to his head. After his competitive fencing career, Gerde became an international referee, and also served as a vice-president of the Hungarian Fencing Association, and was involved with the Hungarian fencing team at the 1928 Olympics. Gerde obtained a degree in law, and later worked for the Budapest Chamber of Commerce. In 1944 he died of cardio-pulmanory complications.
In several sources Mauthausen is mentioned as his POD.