[2] In 1853, Lesca held an official position within the Secretariat of the Ministry of War, responsible for the Spanish military and its overseas territories.

On November 19, 1857 he held the rank of Brigadier General of the infantry regiment in Biscay, a province in the Basque Country, northern Spain, and served as the military governor.

In late 1857 he continued his role as an official of the Ministry of War for Francisco Armero[6] and within the secretariat and archival departments organized for the Military State of Spain and Overseas.

When Cuba's Ten Years' War began in October 1868, he served under Captain General Francisco de Lersundi y Ormaechea.

Following the Las Clavellinas Uprising by Cuban separatists, he was assigned as the commanding general and military governor of Puerto Príncipe (present-day Camagüey).

[11] The brigade led by Juan de Lesca comprised battalions from the King's and Aragon regiments, an engineering unit, and two artillery pieces.