On return to Germany, as the war was declared a few months later in September 1939, which his manoeuvring in London had failed to avert, Schwerin assumed duties as a frontline German military officer, and what followed was an extensive campaign career which took him from fighting in the
Low Countries and France to North Africa, Russia to Germany and Italy. He received command of the 1st Battalion Motorized Infantry Regiment of the
Grossdeutschland Division on the war's outbreak, and took part of the invasion and defeat of France in 1940 (elements of troops under his command in this unit committed two massacres of disarmed French Imperial African
Senegalese Tirailleurs whom they had captured as prisoners of war during the invasion).
Normandy The 116th Panzer Division started crossing the
Seine on 20 July 1944. Schwerin attacked the American positions between
Beaucoudroy and Percy, retaking the former town, but failing to take
Mont Robin. In effect, the division had difficulty advancing in the Normandy landscape. Schwerin complained "Of the 120 armoured vehicles in this area, only a few managed to form a spearhead along the road. Most of the tanks can't cross this land infested with hedges and brushwood. Long queues form behind them. Precious time is lost. The Panzer IV have proven as luckless as the Panthers because they're too wide for the roads we've taken. They find themselves caught between the narrow and high embankments. All these can't be freed, and can't be deployed." He blamed
Hans von Funck for his failure to take Mont Robin.
Operation Luttich On 4 August, he confronted
Raymond O. Barton and
Manton S. Eddy near
Sourdeval. On 6 August, Schwerin was given the mission of advancing toward
Brecey as part of
Operation Luttich the following morning, but on 7 August the
US 28th Infantry Division attacked the
84th Infantry Division at
Gathemo to the right of Schwerin's division. Schwerin, thus exposed to an attack on his right flank, maintained his defensive position, only dedicating half his forces to the mission, a quarter of them after a five-hour delay. On 8 and 9 August, the Allies bombed Sourdeval to cut off Schwerin's supplies. With the failure of the operation, Funck replaced Schwerin.
Battle of Aachen As the American Army's advance crossed the Belgian border into Germany, it approached the town of
Aachen where the remnants of Schwerin's 116th Panzer Division were deployed. By this time, 116th "Division" had been reduced to 600 men, twelve serviceable tanks and was bereft of artillery guns. Coming to the conclusion that his force didn't possess the strength to deny the town to the Allies, and an attempt to do so would be a tactically futile loss of life and endangerment of the town's civilians, several thousand of whom had not been evacuated from what was now about to become the fighting line, and also to try to protect the city's historical architecture and relics from being destroyed - Aachen being the ancient capital and crowning site of the kings of the
Holy Roman Empire - Schwerin unilaterally decided to withdraw from Aachen and declare it an
open town without seeking approval from superior command, in a manner similar to what General
Dietrich von Choltitz had done in Paris two weeks earlier. Schwerin wrote a communique, which he left at the town's post office, for the approaching American commander notifying him of this decision and requesting that he treat the remaining German civilian population humanely. As he was preparing to abandon the town, Schwerin received intelligence from senior command headquarters informing him that the American advance appeared to have halted to re-group, a large scale attack upon Aachen in consequence was not imminent, and notifying him that reinforcements were en route to him for the town's defense. At this moment, an American reconnaissance force appeared in the South-West suburb of Aachen, which Schwerin received orders to counter-attack and bar from entering the town, which he complied with, ordering the 116th Division's grenadiers to engage it and force it back out. Given the rapidly changing situation, he dispatched an officer to retrieve the 'open town' communique that he had left at the post office, but by this time it had fallen into the hands of roaming
Schutzstaffel security police operating in Aachen under the personal authority of Adolf Hitler, who had been sent in to stiffen resistance against any signs of wavering in the line by the
German Army's officer corps. On reading the communique's content, they ordered Schwerin be immediately relieved of command and placed under close-arrest, and organized Colonel
Gerhard Wilck being sent in to replace him at the head of the 116th Division.
Italian Front and surrender With the aid of Field Marshals
Gerd von Rundstedt and
Walter Model, Schwerin received only a severe reprimand for his actions at Aachen. He was then ordered to the Italian front to take over the command of the
LXXVI Panzerkorps in December 1944. At the beginning of April 1945 he was promoted to the rank of General of Panzer Troops. On 26 April 1945 he was captured on the Italian front by the
British Army, becoming a prisoner of war. He was released from post-war Allied military custody in late 1947. ==Post-war==