Pedro Mayorga just missed a medal in team jumping at the 1956 Equestrian Olympic Games, placing fourth. He had won a silver medal in the event with the Argentine team at the 1955 Pan American Games. He later became an administrator in equestrian sport, serving as chef d’équipe for the Argentine teams in the late 1950s and at the 1960 Olympic Games, as well as the team which won the Agan Khan Trophy at the Dublin Horse Show in Ireland. From 1972-76 Mayorga served as a technical delegate for international equestrian events, including the Olympic Games of 1964, 1968, 1972 and 1976. He was made a member of the bureau of the Fédération Equestrian Internationale (FEI) in the late 1950s and became second vice-president in 1965, later moving to first vice-president, a position he held until 1981.