Ong is Executive Deputy Chairman of the S. Rajaratnam School of International Studies (RSIS) at the
Nanyang Technological University in Singapore. He is concurrently Director of the Institute of Defence and Strategic Studies (IDSS) and Head of the International Centre for Political Violence and Terrorism Research (ICPVTR) at RSIS. Ong continues to hold the position of Ambassador-at-Large at the Singapore
Ministry of Foreign Affairs. He is also Singapore’s Non-Resident High Commissioner to
Pakistan and Non-Resident Ambassador to
Iran. Mr Ong was the Chairman of the
Singapore International Foundation (SIF) from 2015 to 2023. Under his charge, the SIF was awarded the Adinata Award for strengthening bilateral ties with Indonesia. Ong was High Commissioner of Singapore to
Malaysia from 2011 to 2014. He served as High Commissioner of Singapore to
India and concurrently Singapore’s Ambassador to
Nepal from 1996 to 1998. Ong served as the 11th Secretary-General of
ASEAN (Association of Southeast Asian Nations), based in Jakarta, Indonesia, for 5 years from January 2003. In 2025, Ong explained that Asean's effectiveness laid in its informal and loose structure that allows them to work out differences and explore possibilities across a diversity of views. Ong started his diplomatic career in 1979 and was posted to the Singapore Embassies in Saudi Arabia, Malaysia, and the United States of America between 1984 and 1994. From September 1998 to December 2002, he was Press Secretary to the then Prime Minister of Singapore, Mr
Goh Chok Tong, while holding senior appointments in the
Ministry of Information, Communications and the Arts, and the
People’s Association in Singapore. From 2008 to 2011, he served as Director of the Institute of Policy Studies (IPS) in the Lee Kuan Yew School of Public Policy at the National University of Singapore. In 2017, in a well-publicised series of exchanges, Ong was one of a few diplomats and politicians who criticised views expressed by former diplomat
Kishore Mahbubani in relation to Singapore's foreign policy. In 2022, then Cambodian Prime Minister
Hun Sen took issue with remarks made by Ong in relation to a visit by Hun Sen to Myanmar. In June 2024, Ong, discussing the 60th anniversary of ASEAN, continued to express optimism about its future, but stressed the need for collaboration in order to advance the prospects of its people. He is also the chairman of Humanity Matters, an inter-faith Singapore based charity that has raised more than $300,000 for the Gaza humanitarian efforts in 2024. ==Awards==