Minh entered military service during the First Indochina War in 1950 as an airborne officer serving in the Vietnamese National Army.

Minh was dispatched to An Giang Province, in the Mekong Delta, and served as provincial chief until Diem's death in 1963.

By 1967 Brigadier general William Desobry, the American senior adviser, considered the 21st Division under Minh the best in the ARVN.

"[2]: 312 Following the May Offensive of 1968, he was given the command of the Capital Military District by his close friend President Nguyễn Văn Thiệu.

"[2]: 485  Following the offensive Minh remained in command of III Corps despite continued American insistence that he be replaced.