Victorino De La Plaza had a distinctly short military career. When the Triple Alliance War began, he abandoned his university studies to join an Artillery Regiment. He was chosen to be an assistant to ; a member of the Argentinian military with a prominent role against the Mapuches and in the Triple Alliance War, who was also Governor of the He fought in the Battles of, , on May 2, 1866, and the Battle of Tuyuti on May 24th of the same year. Subsequently the Government of Uruguay awarded him both the, Silver Sol medal for his actions in the battle of Estero Ballaco and with the award of the, Cords of Honor for his performance at the Battle of Tuyuti. Bartolome Miter, promoted him to the rank of Captain, and have him a mention for his heroism. However, although he had performed exceptionally well he had to return to Buenos Aires due to the fact that he suffered from health problems.