In July 1973, the Central Committee of the Communist Party of Vietnam after its 21st conference issued a resolution of strengthening the armed forces to unify the country.

After the PAVN victory in the Battle of Ban Me Thuot in March 1975, 1st Corps was ordered to move to Southern Vietnam and participate in the 1975 spring offensive.

During the last days of the war, 1st Corps had a major role in the attack on Saigon, in which it was assigned the mission of capturing the headquarters of the Joint General Staff.

The corps was awarded the title Hero of the People's Armed Forces (Anh hùng Lực lượng vũ trang nhân dân) in 1985.

After that, the corps moved into the battlefield along Highway 1 – Road 9 – through Lao Bao to Laotian territory – back to Kon Tum along route 14 through Buon Ma Thuot, on 14 April 1975 to Dong Xoai – Phuoc Long prepares for the final battle.