Bumtsend made his first contact with Mongolian revolutionaries in 1920 while working for the administration of his local hoshuu. He helped collect winter clothing for the partisan army and was involved in propaganda work. He was made a unit commander in the Mongolian partisan army commanded by Damdin Sükhbaatar during the Mongolian Revolution of 1921 and played a role in the defeat of the Chinese garrison at Kyakhta in March 1921. After Mongolian partisans and Soviet Red Army troops successfully entered Khüree in July of that year, Bumtsend's unit participated in several mop up guerrilla operations against remnants Baron Roman von Ungern-Sternberg's forces. His unit then suppressed counterrevolutionary uprisings in eastern Mongolia.