He graduated from the Department of Philosophy at Seoul National University and the Graduate School of Public Administration. He received an honorary doctorate in political science from Inje University and Wonkwang University, respectively. He served as a professor at the Military Academy and later served as an ambassador to Nigeria and Australia, and served as Director of the Institute for Foreign Affairs and Security. As a representative of inter-Korean high-level talks in the early 1990s, he played a leading role in adopting the “Inter-Korean Basic Agreement” and the “Joint Declaration on the Denuclearization of the Korean Peninsula.” In 1995, as secretary-general of the Asia-Pacific Peace Foundation, he formed a relationship with Chairman Kim Dae-Jung. He later served as the Minister of Unification and the Director of the National Intelligence Service in the Kim Dae-Jung government to promote the ‘Peace Process on the Korean Peninsula.’ In June 2000, he met with Chairman Kim Jong-il as a special presidential special envoy and contributed to the successful inter-Korean summit and the adoption of the “June 15 Inter-Korean Joint Declaration.” Afterward, he served as the chairman of the Sejong Foundation and the chairman of the Hankyoreh Unification and Culture Foundation. In 2015, he worked as an advisor to the Kim Dae-Jung Peace Center and chairman of the Korean Peninsula Peace Forum.