 In 1954, Kim Chong-kon was promoted to Lieutenant and a PT boat leader.During his years as field officer, he assumed command of vessels like LSM-613 "Ulleung" (; from August 1, 1956 to November 7, 1957) and PCEC-53 "Hansan" (; from July 5, 1962 to August 3, 1963), later a professor at the Joint Forces Staff College (JFCS) in 1964.On April 6, 1966, he became captain of the destroyer DD-91 "Chungmu" (), and saw combat against a North Korean spy ship at night on October 10.