In December 1941, Grabovenko was drafted into the Red Army and sent to the 455th Rifle Division, forming in the Kemerovo Oblast. The division soon was renamed the 237th Rifle Division. In April 1942, he was transferred along with the division to Vologda in the Arkhangelsk Military District. In July 1942, the division was sent into combat during the Battle of Voronezh. In January 1943, he fought in the Voronezh-Kastornoye Operation. In February and March, he fought in the Third Battle of Kharkov. During July and August, he fought in the Battle of Kursk.