After school he studied at the Faculty of Public Administration of Seoul National University and completed this study with graduation in February 1970. In July 1973, he joined the diplomatic service. During this time he completed postgraduate studies at the Institute of Social Sciences in The Hague, which he completed in July 1974. In February 1976, he was Third Secretary at the Embassy of Japan. After his return he was between December 1979 and July 1981 assistant secretary in the then President Choi Kyu -ha and Chun Doo -hwan office. Then he found a use as First Secretary at the Embassy in Singapore and then from June 1983 to May 1985 as Counsellor ( Counsellor ) at the Embassy in Barbados.
After his return he was again assistant secretary in the office of President Chun Doo -hwan before he Director of the North America division in the Office of American Affairs of the Foreign Ministry was in September 1986. Between January and October 1988, he was Executive Secretary of Foreign Minister Choi Kwang -soo and following Counsellor at the Embassy in the United States. In December 1991, he returned to the Foreign Ministry, where he was Deputy Director General of the Office of American Affairs. After nearly nine months of work in this capacity, he was spokesman for the Foreign Ministry in August 1992.
In January 1994, his appointment came to the Messenger at the Permanent Mission of South Korea to the United Nations in New York. In March 1995 he returned to Seoul and was Secretary for Foreign Affairs by President Kim Young- sam, before 1998, Director General of the Office of American Affairs at the Foreign Ministry was between March 1996 and April. In April 1998, its posting was as ambassador to the embassy in the United States until 2001 when he Special Adviser to the Minister of Foreign Affairs and Trade, Han Seung- soo, was established in August. In December 2001, Foreign Minister Han Seung -soo appointed him as ambassador for Afghan affairs and terrorism.
In March 2002, Yu Myung- hwan ambassador to Israel and after March 2004 to July 2005 Ambassador to the Philippines. In July 2005 he returned to Seoul, where he was until March 2007, the Ministers of Foreign Affairs and Trade Ban Ki -moon and Song Min -soon, Deputy Minister of Foreign Affairs. This was followed by his posting as ambassador to Japan.
On 29 February 2009 he was finally appointed by President Lee Myung -bak as the successor of Song Min -soon to the Minister of Foreign Affairs and Trade in the Cabinet of Han Seung -soo. On September 4, 2010, he offered according to media reports of nepotism, with respect to the employment of his daughter in the ministry, his resignation. His successor as Minister of Foreign Affairs was on 1 October 2010 Kim Sung- hwan.