[1] He was named prime minister of Mongolia's provisional government at the first MPP Congress in March 1921 but was subsequently replaced by Dogsomyn Bodoo after just a month in office.

Other delegates included Soliin Danzan, Dansrabilegiin Dogsom, Damdin Sükhbaatar, Khorloogiin Choibalsan, Dogsomyn Bodoo and Darizavyn Losol.

Chagdarjav was appointed prime minister of the provisional revolutionary government established at a secret MPP meeting in the Russian-Mongolian border town of Troitskosavsk from March 1–3, 1921 (later known as the First Party Congress of the MPRP).

Soon after the victory of the Outer Mongolian Revolution of 1921, strife erupted within the party as various factions jockeyed for power, particularly between Soliin Danzan and Prime Minister Bodoo.

In 1922, Danzan accused Bodoo, Chagdarjav and others of plotting with the charismatic independence leader Ja Lama as well as with the Chinese and Americans, to undermine the revolution and establish an autocratic government.