Ignacio Pérez, the son of Domingo and María Concepción (de Carvajal) Pérez, was born in July 1761, the third of thirteen children, into a family long involved in the military affairs of Texas. In 1781 he married Clemencia Hernández, a granddaughter of Andrés Hernández, founder of one of the province's first privately owned ranches. Pérez devoted considerable attention to stock raising and the accumulation of property at San Antonio de Béxar. In 1804 he purchased from the Menchacas (see MENCHACA, LUIS ANTONIO) the old comandancia, the building known as the Spanish Governors' Palace. In 1808 Pérez received four leagues of land just below the Medina River and astride the Old San Antonio Road to San Juan Bautista. This and an adjoining league between the Medina and Leon Creek served as the base for Pérez's livestock operations. In 1809 he was síndico (commissioner) of all the ranches in his district.
During the revolutionary decade that followed, Pérez remained staunchly Royalist and prospered for his constancy. When the Casas Revolt was toppled at Bexar, Pérez sat on Juan Manuel Zambrano's ruling junta. Likewise, when the capital again fell to the Gutiérrez-Magee expedition, Pérez withdrew with other Royalists and reappeared in Gen. Joaquín de Arredondo's army as a captain of cavalry. He took part in the decisive battle of Medina and rode with Col. Ignacio Elizondo in pursuit of rebels to the Trinity River. For his role in the restoration of Royalist authority in Texas, Pérez was promoted to lieutenant colonel. He soon distinguished himself as a capable Indian fighter in the attacks that swept the weakened province. He served as an interim governor from July 27, 1816, to March 20, 1817. During Antonio María Martínez's administration Pérez was recognized as the leading cattleman of the region and one of its most substantial citizens. In 1819 Governor Martínez sent him to oppose the latest filibustering venture on Texas soil, the Long expedition. Pérez left San Antonio de Béxar on September 27 with some 550 men, soon to be augmented by 100 more when Indians threatened the force. Moving toward Nacogdoches, he captured two small groups of Anglo-Americans. On October 11 and again on October 15, he engaged small detachments of James Long's men. He arrived in Nacogdoches on October 28 and moved on to the Sabine. Long and the remnants of his force had fled, but Pérez remained through November to drive the remaining filibusters out; his return trip to San Antonio was completed on February 2, 1820.
In October 1821 Pérez was again sent to engage Long, who had reorganized his forces at Point Bolivar and had taken the town of La Bahía (now Goliad). The settlement capitulated quickly before Pérez, and on October 8, 1821, Long was made a prisoner and taken to San Antonio. In 1814 Pérez's twenty-four-year-old daughter, Gertrudis, had married Manuel Antonio Cordero y Bustamante, former governor of Texas, who was sixty-one years old at the time. Cordero died in 1823, and Pérez, in the spring, escorted Gertrudis home to Texas from Monclova. Shortly thereafter he died and was buried on October 7, 1823, after a ceremony at Purísima Concepción chapel with an honor guard in attendance. His wife followed him in death in 1825. They had three children and adopted others, including a boy whom the colonel had rescued from the Comanches.