He was appointed as director of the Khmer International Relations Institute, and held that office from 1993 to 1994. when Kao became Director of the think-tank, the Cambodian Institute for Cooperation and Peace (CICP), launched earlier by His Royal Highness Prince Norodom Sirivudh in cooperation with the German Friedrich-Ebert-Foundation (Phnom Phenh Post 09. September 1994). Kao worked as CICP's first executive director for 10 years, until 2004, though he has remained as a Member of the Board of Directors. The CICP helped support Cambodia in becoming a member of the
Association of Southeast Asian Nations (ASEAN) in 1999, the ASEAN Institutes of Strategic and International Studies and the Council for Security Cooperation in Asia Pacific (CSCAP) during Kao's tenure. He has published many books on ASEAN and Cambodian-ASEAN relations, and gained significant experience in ASEAN through the activities of the ASEAN Institutes of Strategic and International Studies. His time at CICP also involved significant interactions with the Royal Government of Cambodia, as an advisor to the Ministry of Foreign Affairs and International Cooperation. He also became a member of the Supreme National Economic Council with the rank of minister when SNEC was founded in 1999 and has been a member since then. Kao was inspired to create a Cambodian higher education institution modeled in a similar way to the United States that focuses on developing students' critical thinking and problem solving skills. and the Asia Faiths Development Dialogue both of which fall under the umbrella of the university. Kao is a founding committee member, and vice-chairman of AEF, which was established by UC in May 2005. AEF is a think-tank promoting policy dialogue around major issues facing the Asia-Pacific region. AEF has generally been held on an annual basis in
Phnom Penh. During his tenure as Secretary of State, Kao worked extensively with
ASEAN, developing relationships and managing Cambodia's participation in the organization's many mechanisms. In addition to ASEAN, Kao was also responsible for the ASEAN Plus Three, the ASEAN Plus One mechanisms, the ASEAN Regional Forum (ARF), the East Asia Summit (EAS), as well as the Asia-Europe Meeting (ASEM) He has also served as a member of the Standing Committee of the
Cambodian Red Cross for two five year terms, from 2008 to 2018. He was Alternative Member for Cambodia's National Representation for the ASEAN Political-Security Council from August 2009 to September 2013, as well as Secretary-General of the ASEAN National Secretariat of Cambodia from 2004 to 2013. In 2013, he was promoted to the position of Minister Delegate Attached to the Prime Minister of the Kingdom of Cambodia, in charge of Foreign Affairs and ASEAN. From October 2016 to May 2017, he served as the vice chairman of Cambodia's Inter-Ministerial Committee for the
World Economic Forum on ASEAN 2017. He currently serves as a Senior Fellow at the
Jeffrey Cheah Institute on Southeast Asia and is also a Member of the Global Council of The Asia Society. In 2018, he was appointed to serve on the Board of the Cambodian Higher Education Association (CHEA) as both the Deputy Chairman of the Board of Directors and the Chairman of the Dissemination Affairs Committee. In September 2018, he was reappointed for a second term as Minister Delegate Attached to the Prime Minister of the Kingdom of Cambodia in charge of Foreign Affairs and ASEAN, from 2018-2023. In August 2022, Kao was appointed as the next Secretary-General of ASEAN at the plenary session of the 55th ASEAN Foreign Ministers' Meeting, and it is the first time a Cambodian will have held the post. In November 2022 at the ASEAN Summit in Phnom Penh, all ASEAN leaders supported his appointment. == ASEAN Secretary-General ==