Edward Baca enlisted in the Army in November of 1956 with the 726th Anti-Aircraft Artillery Battalion of the New Mexico Army National Guard. Upon graduation from Officers Candidate School in July 1962, he was assigned as a platoon leader of the 3631st Maintenance Company. Soon after, he volunteered for active duty and for overseas deployment to Vietnam. Baca was released from active duty in 1966 and returned to the New Mexico Army National Guard, where he assumed command of the 3631st. In 1977 Baca became the state military personnel officer and was assigned the state assistant, G-1. A short time later, he was appointed the adjutant general, New Mexico National Guard. Commanding both the Army and Air National Guard of New Mexico, Baca led the state guard to a position of national prominence as a vital component of the "total force."

Baca spearheaded a nationwide National Guard force modernization effort and directed the first fielding of the Chaparral and Hawk missile battalions in the Reserve. The National Guard Bureau designated New Mexico's award-winning drug demand reduction program as a pilot for all states and in October of 1994, Baca was promoted to lieutenant general and assigned as chief, National Guard Bureau, a position he held until his retirement in 1998.