Said to have studied agriculture at the Ateneo de Manila, San Miguel took on odd jobs including sewing and "inspecting" the hacienda of Don Pedro Roxas in Nasugbu, Batangas. When the Revolution broke out, he joined the Katipunan, Magdiwang chapter, in his hometown, whose more famous members were the father and son tandem of Mariano and Santiago Alvarez and Arternio Ricarte.

He led a unit of rebels in garrisoning Nasugbu, later defending it against the Spanish forces headed by a Colonel Pazos. Outgunned and outnumbered, San Miguel and four other surviving defenders lost Nasugbu to the enemy. Impressed by his courageous performance, his Magdiwang superiors immediately promoted him to brigadier-general, but this was however withdrawn when the revolutionary army underwent reorganization. 

From March to April 1897, as the commander of the rebel lines in San Francisco de Malabon, he ferociously stalled the enemy's triumph by continuously pushing back towards Noveleta the troops of General Lachambre.

He was one of the first officers to heed Aguinaldo's renewed call for revolution when the latter returned to the country in May 1898. He was tasked with the supervision of the uprising in several provinces in Luzon including Pampanga, Manila, Morong, Laguna, Batangas, and Cavite. It was his movement in Cavite, however - the capture of thousand captives and enemy weaponry - that catapulted his name to revolutionary prominence.

In the early days of the war against the Americans, San Miguel led his soldiers against the fierce attacks of the enemy in San Francisco del Monte. Like his fellow Filipino warriors, he and his men gave a brave, but eventually doomed, struggle against an enemy that proved a hundred times mightier than the Spaniards.

Hoping to reverse the trend of the war, with the revolutionists slowly losing to the enemy, he resolved, in late 1899, to resurrect the Katipunan. On December 6, he issued a circular to this effect among his officers and troops in Zambales. The idea of a resurrected Katipunan quickly caught fire and spread from there to the Central Luzon provinces, to the llocos in the North and to Manila in the South.

In October 1902, he was elected "Captain-General" and supreme commander of the remaining revolutionary forces. He gathered his forces and embarked on a guerilla struggle that tested the might of the enemy, thereby becoming one of the most wanted leaders by the authorities.

He died defending his Motherland in the battle of Corral-na-Bato in Morong (now Rizal), on March 27, 1903.