one of the chief military politicians of 19th-century Spain. He played an important part in the Revolution of 1868, which dethroned the Bourbon Spanish queen Isabella II.

Serrano joined the army at the age of 12 and fought with the forces of Isabella II against her uncle Don Carlos (First Carlist War, 1833–39). He later came to exercise influence on the queen but was eventually removed from court. He took part in the successful revolution by the moderate General Leopoldo O'Donnell (O'Donnell, Leopoldo, Duque De Tetuán) in 1854. He served as captain general of Cuba (1859–62), and in 1867, upon the death of O'Donnell, Serrano succeeded him as head of the Liberal Union Party.

After the Revolution of 1868, Serrano became chief of the executive power, but political preeminence rested with Juan Prim y Prats, the prime minister. Serrano served as regent until January 1871, when Amadeus of Savoy became king. On Amadeus's abdication (February 1873) and the formation of the First Republic, Serrano went into exile in France. But, after the coup d'état of January 1874, Serrano again headed the government until he was once more driven into exile upon the accession of Alfonso XII in December 1874. Serrano decided to recognize Alfonso in 1881, and he resumed his political career. In 1884 he was named Spanish ambassador to Paris.