José Antonio Romualdo Pacheco was a Californio, born in Santa Barbara, California to a family with prominent connections. His father, José Antonio Romualdo Pacheco, had moved to Alta California from Guanajuato in 1825, and served as an aide to José María de Echeandía during his tenure as Governor of Alta California. Pacheco's father was killed at the Battle of Cahuenga Pass in 1831, when the young Romualdo was just five weeks old. His father had shot Jose Maria Avila, who had attacked Alta California Governor Manuel Victoria with a lance, but died when Avila's lance struck him.