Revolutionary Insurrectionary Army of Ukraine
Koshevoy was born on in Oleksandriia, Kherson Governorate to a Ukrainian peasant family. After graduating from primary school in 1919, he worked with his father, a miller, for a year and a half. He joined the Red Army during the Russian Civil War on 13 February 1920 and was sent to the 2nd Red Cossack Regiment of the 8th Red Cossack Cavalry Division, with which he fought on the Southwestern Front against Polish and Ukrainian People's Army troops in the area of Chornyi Ostriv, Lityn, Proskurov, Horodok, and Rohatyn, then against the Revolutionary Insurrectionary Army of Ukraine.