Ponticelli was not a French citizen and in May 1915, when Italy entered the war, he was forced into the Italian Army by conscription. Even though he tried to stay with his French regiment, he had to become part of the 3rd Alpini Regiment. Ponticelli fought against the Austro-Hungarian Army at Mount Piccolo on the Austria–Italy border. At his new job as a machine gunner, Ponticelli was wounded by a shell during an assault on an Austrian mountain. He was sent back to his job after rest in Naples.