Supreme Council for National Reconstruction
After he was promoted to brigadier general in August 1958, he served as the combat staff of the First Field Army, commander of the 38th Infantry Division, and the commander of the 5th Infantry Division. He led the 5th Infantry Division and participated in the May 16 Coup in 1961, which led to installing a reformist military Supreme Council for National Reconstruction effectively led by Park Chung-hee and led to end of the Second Republic of Korea.