Born Oct. 1, 1893, on Hiiumaa Island; died Sept. 3, 1919, near Izborsk. Active in the revolutionary movement in Estonia. Member of the Communist Party from March 1917. Son of a poor peasant; a worker.
After the February Revolution, Koolmeister was chairman of the construction workers’ trade union in Tallinn and a member of the Tallinn Soviet. He was a delegate to the First and Second All-Russian Congresses of soviets. He was a member of the Council of Workers’ Control in Tallinn after the October Revolution of 1917. In February 1918 he became chief of the Estonian Department of the People’s Commissariat of Nationalities of the Union of Communes of the Northern Oblasts in Petrograd. Koolmeister engaged in party work in Estonia from November 1918. In August 1918 he was a member of the first trade union congress in Estonia, which called for an end to the intervention against Soviet Russia.The bourgeois government disbanded the congress and arrested 102 of its delegates, of whom 25, including Koolmeister, were shot.