Chatri Archjananun started his career working at one of the leading international law firms in Bangkok. In 1993, Chatri joined the Ministry of Foreign Affairs of Thailand and began his career in diplomacy. For over 30 years, Chatri held various prestigious positions, including the Director of Legal Affairs Group and Deputy Director-General of the Department of Treaties and Legal Affairs. He has been well respected with vast and impressive experiences in providing legal advice to the Ministry of Foreign Affairs, the Royal Thai Embassies in various countries around the world, and the Royal Thai Governments on wide range of domestic and international legal issues, including diplomatic and consular protections, international human rights law, dispute resolution, international environmental law, and constitutional law.

Chatri was selected on secondment to the Ministry of Commerce of Thailand and held a position at the Permanent Mission of Thailand to the World Trade Organization and the World Intellectual Property Organization between 2012 and 2016 where he also gained invaluable experiences and networks in international trade laws. In 2017, he rejoined the Ministry of Foreign Affairs and was appointed as the Director-General of Consular Affairs, where he was the leading officer in concluding the Ministry's sole mega project on e-passport contract worth Baht 10,000 million.

He was subsequently appointed as the Ambassador Extraordinary and Plenipotentiary of the Kingdom of Thailand to the Kingdom of the Netherlands between 2020 and 2024.

He retired from his Government service in 2024 and had been bestowed the Royal Decoration, Knight Grand Cordon (Special Class) of the Most Noble Order of the Crown of Thailand upon his retirement. He currently continues to actively contribute to the field of international law and diplomatic in Thailand by imparting his knowledge, invaluable insights, and decades of professional experiences to university students across the countries with strong intentions of giving back to the society.

Chatri obtained his LL.B from Thammasat University, Thailand; an LL.M from Hull University, the United Kingdom; and the Diploma in International Trade Law from Turku University, Finland. He was selected by the Ministry of Foreign Affairs to attend several high-level training courses for executives at the Judicial Training Institute, the Court of Justice and at the College of the Constitutional Court.