Spanish military. At the age of fourteen he became part of the crew of the ship Neptuno, in Havana, the commander being the frigate captain Rosendo Porlier Asteguieta, his paternal uncle. Arrived in Cádiz in 1802 Díaz Porlier entered the Academy of Pilots and Intendants of the Royal Navy.

In 1805, uncle and nephew participated in the battle of Trafalgar aboard the Prince of Asturias. Once disembarked, as a result of the state in which the Navy was operating, Díaz Porlier requested a regiment as his destination, being appointed a captain in the Mallorca Infantry Regiment a year later.

At the beginning of the war of independence, with twenty years of age, Díaz Porlier is framed in the so-called Army of Extremadura, as lieutenant colonel of Grandees. Despite suffering important defeats from Espinosa de los Monteros and Gamonal, Porlier began to stand out for his bravery and professional expertise. In 1809, his party carried out small-scale operations, until achieving the capitulation of the French garrison at Aguilar de Campóo. This success earned him the promotion to brigadier granted by the Central Board.

In February 1811, the Regency appointed Porlier commander general of the Vanguard of the 7th Army (made up of 33,230 men) and gave an official character to his division: 6,450 soldiers, organized into five Infantry Regiments and one of Hussars. The 7th Army grouped the five guerrilla divisions - Cántabra (Díaz Porlier), Ibérica (Longa), Vascónica (Renovales), Navarra (Espoz and Mina) and Castellana (Merino) -, which operated north of the Duero.

On May 26, 1811, the Regency Council granted him a license to marry Josefa Queipo de Llano and Ruiz de Saravia, daughter of the 6th count of Toreno and sister of the most famous of the Toreno, who requested the help of Great Britain and stood out as a Cadiz deputy. His marriage linked him even more to the Principality, where he founded, in June 1811, the Cavalry Academy of the 7th Army.

After the victorious campaign of 1812 and the appointment of the Duke of Wellington as generalissimo of the National Armies, Porlier's division was assigned to the so-called 4th Army or Army of Galicia, under the command of General Castaños. The successes obtained in León, Valladolid, Palencia, Asturias and Santander led the Regency to promote him to the rank of general. At this stage, he received the nickname "el Marquesito" or "El Marquesillo".

On August 31, 1813, the Galician Army in San Marcial managed to push back the imperial troops that had undertaken the offensive against the allied army led by the Duke of Wellington. The French were forced to cross the Bidasoa, thus ending the War of Independence. In recognition of the merits contracted in San Marcial, the Regency granted Díaz Porlier the job of field marshal.

After the war, Díaz Porlier matures his disagreement with the violation of the Cadiz Constitution at the hands of Fernando VII and with the regime that emerged from the Manifesto of the Persians.

His own secretary, Agapito Alconero, betrays him, providing justice with very compromising letters, at times of great political repression, aimed at facilitating the flight to England of José Fernández de Queipo, political chief of Segovia and fiancée of one of his sister-in-law. He was arrested in Madrid on May 29, 1814, and tried for the alleged crime of disloyalty. He is sentenced to four years in prison and to serve them is taken to La Coruña, being locked up in the Castillo de San Antón.

In mid-1815, on the pretext of needing a hydrotherapy treatment at the Aretixo spa for medical reasons, Díaz Porlier obtained permission to reside in the nearby town of La Pastoriza. Here, with the complicity of his escort Captain Castañera, he prepares the pronouncement that begins on his return to La Coruña on the night of September 18 to 19, 1815. With the help of several Asturian officers who had fought alongside him, he made prisoner to the captain general and the military authorities, proclaiming the Constitution of 1812.

On September 21, at the head of several rebellious bodies, including almost all the military forces stationed at the Ferrol naval base, Porlier went to Santiago de Compostela with the intention that the authorities and military bodies quartered there would join the pronouncement. During a break on the road, at the entrance to the town of Ordes, Porlier was betrayed by a group of sergeants who managed to arrest him and hand him over to the troops of the Compostela garrison. When the outcome of the expedition was known in La Coruña, and it was learned that Porlier was imprisoned in Santiago, all those who had joined dispersed.

Five days later a summary court-martial sentenced him to die by hanging, in accordance with the provisions of the Ordinances of Carlos III for those convicted of sedition. Once the sentence was ratified by the Monarch, on October 3 he proceeded to his military degradation, execution and burning of the proclamations that he had ordered printed.