He fought for the Finnish Red Guards in the 1918 Civil War and in the 1918–1919 Allied North Russia Intervention ranked as a British Navy officer.

Before the Battle of Tampere in April 1918, Orjatsalo managed to flee to Helsinki and later to Soviet Russia where he met the Finnish communist leader Otto Wille Kuusinen in Moscow.

On his advice, Orjatsalo joined the Murmansk Legion which was a British Royal Navy organized military unit during the 1918–1919 Allied North Russia Intervention.

[4] Orjatsalo and some 20 other high-ranked Murmansk Legion officers were forced to leave to England or North America, as they were condemned by both the Finnish Government and the Russian Bolsheviks.

Because of the mass amnesties of the former Red Guard fighters, Orjatsalo was able to return Finland in 1929, but after the rise of radical right-wing Lapua Movement he had to flee the country again in 1932.