 On 1970, he officially gained the rank of Rear Admiral lower half, becoming commander of South Korean Navy's 2nd Flotilla.Other major assignments included the commander of Inchon Guard District (1971), Deputy Chief of Staff for G3-Operations, commander of the naval station (1973), commander of the Korean Fleet (1975) and Vice Chief of Naval Operations (1977).On April 16, 1979, he was promoted to full Admiral and was appointed as the 12th Chief of Naval Operations.