Assigned to the Red Army's General Staff Academy as a senior instructor after returning from China, Cherepanov was next named Chief Inspector for the Northwestern Direction following the June 1941 German invasion of the Soviet Union in July 1941. He subsequently led the 23rd Army from September 1941 until July 1944, and was promoted in rank to lieutenant-general on 1 September 1943. His troops took part in the defense of Leningrad and joined in the summer 1944 breaking of the siege and forcing of Nazi Germany's co-belligerent partner Finland to relinquish its positions Karelian Isthmus near Leningrad. The combined Soviet gains compelled Finland to negotiate the Moscow Armistice in 1944.