[3] His father worked for a socialist party associated with the army chief who staged Myanmar's first coup in 1962, ushering in nearly half a century of isolationist military rule.

He concurrently served as Ambassador to Switzerland, as well as Permanent Representative to the World Trade Organization (WTO) and to the Organisation for the Prohibition of Chemical Weapons (OPCW).

Kyaw Moe Tun stated his intention to continue to represent the democratically elected government of Myanmar, whose officials had either been exiled, imprisoned, or gone underground.

[11][12] On 1 March 2021, he sent letters to the General Assembly president and UN Secretary-General António Guterres saying he represents the country's legitimate government and remains Myanmar's ambassador.

The two men were charged with conspiring with a Thai arms dealer to "seriously injure or kill" Tun in an attack on the ambassador in his Westchester County, New York home.

[19] A behind-the-scenes compromise between the US and China, prevented the Burmese military's representatives from attending the session, effectively forestalling a decision to replace Kyaw Moe Tun.

[21] In the 2022 special session of the General Assembly, Tun as Burmese ambassador to the UN, cast his country's vote in favor of Resolution ES-11/1, condemning Russia for its invasion of Ukraine.