At the start of the First World War, Kirchbach had reached the rank of General of the Cavalry, took over the I Corps and was the commanding general in Krakow. His corps advanced on the left flank of Viktor Dankl von Krasnik's 1st Army at the beginning of the offensive against Russia. During the August fighting his I Corps, operating north of the Tanew, contributed decisively to the victory at Kraśnik. When Dankl's army was forced to retreat during the Battle of the Vistula River in October, his corps reached Ivangorod and Kirchbach temporarily took over command of an army group south of the Vistula. In the aftermath of the successful Gorlice–Tarnów Offensive (May 1915) his corps reached the eastern bank of the Bug River in June 1915 and the Ikva River near Dubno in August 1915.