Although raised in a military family that participated in the various events that affected Texas, Perez became a wealthy landowner and cattle rancher in San Antonio, Texas, and in 1809 he was appointed commissioner of the ranches located in that region.
Perez always maintained a loyalty to the Spanish Monarchy, even during the New Spain War of Independence, which began in 1810.
During the war, he occupied the position of captain of cavalry and participated in the battle of Medina.
In 1819, following Martinez' orders, Perez led an army of 550 men (later increased to 650 when they were attacked by Native American groups) to fight the American Filibuster that had invaded several places of Texas, capture them and expel them of Texas.
In 1821, Perez had to face James Long again, who had had a prominent presence among the filibusters in the 1819 conflict, as he had formed a new troop, thus succeeding to besiege La Bahía.