Baltušis-Žemaitis was one of the few Lithuanian officers (others included Vytautas Putna, Ieronim Uborevich, Viktoras Penkaitis) of the Imperial Russian Army who after the February and October Revolutions went to serve in the Red Army. He was a lecturer/docent at the Frunze Military Academy in 1935–1940. Baltušis-Žemaitis briefly commanded the Lithuanian Army in 1940 during Lithuania's incorporation into the Soviet Union. He earned his Candidate of Military Sciences academic degree in 1940. He was also a senior lecturer at the USSR General Staff Academy during 1940–1941 and 1943–1945, and served as the chief of USSR Supreme Command Courses 1945–1947.