Spanish statesman who, as prime minister from 1743 to 1754, pursued a vigorous reform policy that succeeded in advancing internal prosperity and promoting military strength.

Ensenada owed his early advancement to the chief minister of King Philip V (reigned 1700–46), José Patiño (Patiño, José Patiño, marqués de), who put him in charge of work at the new naval arsenal at El Ferrol. Ensenada accompanied the successful expedition against Oran, Algeria, in 1732. Four years later he organized the expedition to Naples that put Philip's son Carlos on the Neapolitan throne and was rewarded with the title of marqués. He also carried out various diplomatic missions in Italy and helped negotiate an alliance with France (the Second Family Compact (Famille, Pacte de)) in 1743. Ensenada was appointed prime minister that year.

An able and effective administrator, Ensenada encouraged the development of agriculture and industry, undertook public works, sought to reform tax collection methods, fostered education, and removed abuses in the customs system to help facilitate internal commerce. He also stimulated the development of the army and especially the navy, building up both the Atlantic and Mediterranean fleets.

In foreign affairs Ensenada took a generally pro-French yet independent stance and regarded England with some hostility as a rival in the Americas. This attitude aroused resentment in the court and helped contribute to intrigues by the British ambassador that brought about Ensenada's downfall (1754) and his banishment to Granada. Ensenada was received at court after the accession of Charles III in 1759 and served as a member of a commission on taxation reform. Because of his pro-Jesuit views, he was once more banished in 1766 and thereafter took no further part in public life.