He returned to Thailand in 1984 to his teaching position at Thammasat and ran for a Parliamentary seat from Nakom Sri Thammarat, his home town. He has been returned to Parliament eight times since 1986. As an MP, he was appointed Secretary to the Speaker of the House of Representatives (Chuan Leekpai), Secretary to Deputy Minister of Interior, Deputy Minister for Foreign Affairs during 1992-1995 and Minister of Foreign Affairs from 1997 to 2001. He served as Chair of the ASEAN Ministerial Meeting and the Chair of the ASEAN Regional Forum (ARF in 1999-2000. In September 1999, while the ASEAN Chair, he led the efforts to get Southeast Asian governments to help restore law and order and that joint undertaking with the support of the United Nations and the international community, brought about peace and security in East Timor