He is mostly known for his capture of insurgent leaders Miguel Hidalgo, Ignacio Allende, José Mariano Jiménez, and Juan Aldama at the Wells of Baján, Coahuila in 1811.

Initially a supporter of Mexican independence who converted to the royalist cause, Elizondo is sometimes compared to the American Benedict Arnold.

Two years later, he was appointed Captain of the Punta de Lampazos provincial dragoons, one of the largest military units in the New Kingdom of León, present day Nuevo Leon.

In 1806, the governor of Nuevo León, Pedro de Herrera y Levya, appointed him to command the Eighth Dragoons, a company, which would operate in Texas against the frequent Apache attacks taking place.

[2] The Mexican War of Independence from Spain began with the "grito" of the Roman Catholic priest, Miguel Hidalgo y Costilla, on September 16, 1810.

[4] Elizondo was asked to continue to pretend to support the rebels to gain intelligence about the plans of Allende and Hidalgo who were then in flight toward the United States after a military defeat in the Battle of Calderon Bridge.

[5] The royalist sympathizers in Monclova included a group of large landowners of the region led by José Melchor Sanchez Navarro.

[10][11] On March 29, 1813, the royalist army in Texas lost the Battle of Rosillo Creek and on April 1 the rebels occupied San Antonio.

With a force of 1,050 men Elizondo crossed the Rio Grande on June 12 and, against Arredondo's orders, camped near San Antonio de Bexar and demanded Gutiérrez's surrender.

[13] Elizondo's last military service to the King of Spain was as the officer in command of a contingent of 500 cavalrymen dispatched by Arredondo from the capital at San Antonio, to chase and mop-up the fleeing survivors of the insurgent army immediately after the Battle of Medina.

His last reports (before the incident that led to his death on his return from this successful mission) detail his march along the Camino Real toward eastern Texas, where he captured and executed many of the rebel soldiers at the Spanish hacienda of Trinidad de Salcedo (1807-1813) on Trinity River, which he depopulated and burned (see translation of Elizondo's final reports appended here).

[15] On September 3, 1813, Elizondo was critically wounded by Lieutenant Miguel (or Manuel) Serrano, while sleeping in his encampment at the edge of the Brazos River.

Many historians believe he was buried on the bank of the San Marcos River, in Texas, New Spain, where he died as he was being carried back to the capital on a litter.