Was a career diplomat. Served as Ambassador of Thailand to the Soviet Union, Indonesia, Germany, Japan and the United States.
His first posting as a third secretary was in Brussels (1975 – 1979) serving concurrently to the Royal Thai Embassy and to the Thai Mission to the European Community (European Union).
After his retirement from the Ministry of Foreign Affairs in 2005, he became a political activist and then politician by joining the Democrat Party. He became the Thai Foreign Minister under the Abhisit – led Government (2008-11) and later a member of parliament (Party-list) in the opposition (2011-13). A member of the National Reform Steering Assembly (2015-17); responsible for the enhancement of democratic political culture.
He is a guest lecturer at many universities; a columnist with the Naewna Daily Newspaper. He is active in APHR (ASEAN Parliamentarian or Human Rights; a member of the Asia Pacific Leadership Network for Nuclear Non-Proliferation and Disarmament (APLN). He sits on the Board of Freeland, a non-governmental organization on anti-traffickings. An outspoken critic on domestic and international issues pertaining to Thailand and ASEAN. Advocator of good governance, anti-corruption and participatory democracy.