機甲師団
After serving in Poland, the 1st Light Division returned to Germany, where it began converting to a Panzer division. However, shortly after this process began, Frölich was appointed the commander of the 78th Panzer Artillery Regiment, which was part of the 7th Panzer Division, led by "Generalmajor" Erwin Rommel. He remained in command of the regiment throughout the Battle of France and then in Operation Barbarossa, where it was particularly effective in supporting the division as it advanced towards Moscow. Apart from a period in France while the division was resting after being heavily involved in the offensive mounted by the Soviet Army over the winter of 1941–42, Frölich served on the Eastern Front until after the Battle of Kursk in July 1943. He was then given command of the 36th Infantry Division, which he led for only a few weeks before appointed commander of 8th Panzer Division in late September. His new command was then serving on the Eastern Front and would be in extensive action for several months. In December 1943, he was awarded the Knight's Cross of the Iron Cross and promoted to "generalmajor".