He was one of the most important aristocrats of his time and held, among other titles, the dukedoms of Alba de Tormes and Berwick, the Countship of Lemos, Lerín, Montijo and the Marquessate of Carpio.

His godparents were his paternal grandfather, Jacobo Fitz-James Stuart, 15th Duke of Alba and his maternal grandmother María del Pilar Ossorio y Gutiérrez de los Ríos, 3rd Duchess of Fernán Núñez.

After returning to Spain, he continued with his higher education enrolling in the Universidad Central de Madrid, where he obtained his bachelor's degree in law.

During the Spanish Civil War, the Communists occupied his residence, the Palace of Liria, which his daughter later restored, and they murdered his younger brother Hernando Carlos María Teresa Fitz-James Stuart y Falcó (1882-1936).

In fact, King George VI was warned of this possibility in October 1943, as his Private Secretary Sir Alan Lascelles reported in his diary, and advised not to say anything that he did not want to reach the enemy.