Question: Did the American Expeditionary Forces (AEF) ever face off against the Imperial and Royal (K u K) forces of the Austro-Hungarian Empire in the Great War?
Answer: Yes, in three cases that I can find.
1. The Western Front
|Some of the Empire's Soldiers on the Western Front|
Kaiser Karl had actually agreed that six Austro-Hungarian Divisions would be transferred to the Western Front, and although this number was never reached (four eventually seeing service there) initially just two were despatched in July 1918. These were the 1st Infantry Division and the 35th Infantry Division plus some heavy artillery. Both divisions were assigned to Army Group Gallwitz, the 1st Division to the German 5th Army, east of the Meuse, and the 35th Division to Army Detachment C Southeast of Verdun in the St. Mihiel Salient.
The 35th Division then saw action in the St. Mihiel Salient on 12 September 1918. Caught by surprise, the division suffered heavy casualties with the remaining troops withdrawing to the Michael Line.
The 1st Division was deployed on the east side of the Meuse, when the U.S. First Army forced a crossing on 8 October 1918. They resisted the American advance around Sivry for three days before being forced back. In this action Oberstleutnant Rudolph Popelka of Infanterie-Regiment Nr. 5 became the only foreign non-general, to be awarded the Pour le Mérite for his valorous service.
2. Italian Front
In the aftermath of Italy's Caporetto disaster American units were sent to the Italian Front. These included the 332nd Infantry Regiment, which joined the pursuit against Austro-Hungarian forces in the Vittorio Veneto victory offensive, which ended the war in Italy. The regiment suffered two casualties in the operation.