He served for 33 years in foreign affairs and national security, including as Minister-Counselor at the Embassy of the Republic of Korea in China and Consul General in Shenyang. During his four years in Shenyang, the diplomatic post closest to North Korea, he gained extensive field experience in inter-Korean relations, reunification issues, and the role of the Korean expatriate community in relations with North Korea.
After retirement, he taught Northeast Asian international relations and Sino–North Korean relations at Kwangwoon University and Hallym University. He earned doctoral degrees from Seoul National University, National Chengchi University, and Hanyang University. He is currently a regular columnist for the China commentary section of Naeil Shinmun and author of Partners in Conflict and Cooperation: The Strategic Symbiosis Between North Korea and China.