When the Red Army was retreating from Courland, Grīns deserted in Bauska and joined a Latvian brigade under Colonel Jānis Balodis.
After the liberation of Riga, Grīns resumed his medicine studies at the newly established University of Latvia in autumn 1919.
After 1920 Grīns worked as a journalist, first in the military newspaper Latvijas Kareivis, and later in Latvis and Brīvā Zeme.
In June 1941 several hundred Latvian officers from this camp, including Grīns, were arrested by NKVD.
Other notable works are Nameja Gredzens (Ring of Namejs), about ancient Semigallian duke Nameisis, and Tobago, about Courlander colonists of the island in the 17th century.
Besides novels, he has also translated into Latvian Erich Maria Remarque's All Quiet on the Western Front and L. Renn War'.