Born in Ferrol, Galicia, Montojo studied at the Naval School in Cadiz, and was assigned as a Midshipman in 1855. By 1860, he had become a Sub-lieutenant and fought against the Moros of Mindanao in the Philippines before returning to Spain in 1864.
Montojo fought in the Battle of Abtao and the Battle of El Callao under Admiral Casto Méndez Núñez against Peru and subsequently assumed a post at the Secretariat of the Admiralty. He was promoted to the rank of Commander in 1873. His new duties included commanding several warships in Havana's naval station as well as those in the Río de la Plata.
Montojo returned to the Philippines again as Rear-Admiral, serving as general commander of all Philippine naval stations. At the outbreak of the Spanish-American War, Montojo was in command of the Spanish Squadron that was destroyed by the U.S. Asiatic Squadron in the Battle of Manila Bay on May 1, 1898. Montojo was wounded during this battle, as was also one of his two sons who were participating in this battle.
By a September 1898 decree, Montojo was relieved of his duties. Moreover, he was ordered to appear before a Supreme Court-Martial in Madrid. Montojo left Manila in October 1898 and arrived in Madrid on November 11, 1898. In March 1899 he was court-martialed and imprisoned. He was later absolved. Among his defenders was his onetime opponent in battle: Admiral George Dewey.
Montojo, however, was discharged from the Spanish Navy.
- (English) Battle of Manila Bay, 1 May 1898 from Naval Historical Center
- (English)Profiles of Key Persons in the Spanish American War
- (English) Admiral Patricio Montojo y Pasarónes:Patricio Montojo y Pasarón