Dr. Oh Ei Sun is the principal adviser at Pacific Research Centre of Malaysia and Senior Fellow at Singapore Institute of International Affairs. He was Senior Fellow at the S. Rajaratnam School of International Studies, Nanyang Technological University, Singapore. His research interests include the political economy of Southeast Asia and international relations, particularly those involving China and the United States.
Ei Sun is also the chairman of KKIP Aerospace Sdn. Bhd., a Sabah government-owned company pioneering the aerospace industry in Sabah. Additionally, he is a chartered fellow of Chartered Institute of Logistics and Transport (CILT), Malaysia, and the vice-chairperson of its Sabah chapter.
Previously, Ei Sun served as Political Secretary to the Prime Minister of Malaysia. He was also senior research fellow and lecturer at various public and private universities in Malaysia, China, Australia, and the United States.