After being promoted to colonel in 1959, Blanchard assumed command of the 2nd Airborne Battle Group, 503rd Infantry, 82nd Airborne Division, and subsequently served as the G-3 of I Corps in Korea. In 1966, he went to South Vietnam and served as Assistant Division Commander, 1st Cavalry Division (Airmobile), and later served as Chief of Staff, I Field Force, Vietnam. After his time in Vietnam, he was assigned as Director of Special Warfare in the Office of the Deputy Chief of Staff for Military Operations; and Director of Plans, Programs and Budget for two major Army General Staff organizations, and he served as executive officer to two Secretaries of the Army.