In 1941, during Operation Barbarossa, Heinrici served in the 4th Army under Günther von Kluge as the commanding general of the XXXXIII Army Corps during the Battle of Białystok–Minsk, the Battle of Kiev and the Battle of Moscow. He received the Knight's Cross of the Iron Cross in 1941. Late in January 1942, Heinrici was given command of the 4th Army. On 24 November 1943 he was awarded the Oak Leaves to his Knight's Cross for his leadership during the Battle of Orsha, during which the 4th Army taking defensive positions near the Orsha region in Belarus, temporarily halted the advance of the Western Front led by General Vasiliy Sokolovsky. During the 4th Army's retreat, it inflicted heavy losses on the advancing Red Army. These successes contributed greatly to Heinrici's reputation as a defensive specialist. Later in 1943 he refused to obey an order to destroy the city of Smolensk by fire before the German army's retreat, and he was temporarily dismissed from his post as commander.