With his younger brother Raimondo D'Inzeo, also an officer in the military (but of the Carabinieri), in the international arena they have been called the brothers invincible equestrianism Italian. They participated in numerous competitions in Italy and abroad. At the Olympic Games in 1960 in Rome, Raimondo won the gold medal and Piero the silver medal in the Grand Prix jump obstacles. They were the first athletes to compete in eight Olympic games, consistently from 1948-1976. Piero won 2 silver and 4 bronze Olympic medals. He also won the European Championship title in 1959.