After the February Revolution of 1917, Żeligowski became one of the organizers of the Polish Army in the former Russian Empire. Initially commander of an infantry regiment in the ranks of the Polish 1st Corps, he was quickly promoted and given command over a brigade. In 1918 he started the creation of a Polish unit in the area of Kuban, which eventually became the 4th Polish Rifle Division. As part of the Polish Army, his unit fought alongside the Denikin's Whites in the Russian Civil War. In October of the same year he became the Commander in Chief of all the Polish units fighting in Russia.