Ban Ki-moon of the Republic of Korea is the eighth Secretary-General of the United Nations.
At the time of his election as Secretary-General, Ban was his country’s Minister of Foreign Affairs and Trade. His long tenure with the Ministry included postings in New Delhi, Washington D.C. and Vienna, and responsibility for a variety of portfolios, including Foreign Policy Adviser to the President, Chief National Security Adviser to the President, Deputy Minister for Policy Planning and Director-General of American Affairs. Throughout this service, his guiding vision was that of a peaceful Korean peninsula, playing an expanding role for peace and prosperity in the region and the wider world.
Ban has long-standing ties with the United Nations, dating back to 1975, when he worked for the Foreign Ministry’s United Nations Division. That work expanded over the years, with assignments as First Secretary at the Republic of Korea’s Permanent Mission to the United Nations in New York, Director of the United Nations Division at the Ministry’s headquarters in Seoul and Ambassador to Vienna, during which time, in 1999, he served as Chairman of the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization.
Ban has also been actively involved in issues relating to inter-Korean relations. In 1992, as Special Adviser to the Foreign Minister, he served as Vice-Chair of the South-North Joint Nuclear Control Commission following the adoption of the historic Joint Declaration on the Denuclearization of the Korean Peninsula.
Source - http://www.un.org/sg/biography.shtml