In early October 1944, the 9th Armored Division landed in France and was immediately deployed eastward to advance into Luxembourg. When the Germans began their Ardennes offensive on December 16, 1944, the "Phantom" division was deployed just north of Diekirch, a few miles east southeast of Bastogne, Belgium. As the Germans attacked U.S. positions near St. Vith on the northern sector of the front, part of the 9th was transferred to assist in defending the city. The units of the 9th Armored Division engaged in fierce combat that bought the U.S. commanders time to organize the defense of Bastogne in which became known as the Battle of the Bulge. By the time they withdrew to the eastern outskirts of the town, the units of the 9th had withstood repeated attacks on the roads leading to Bastogne.

On March 7, 1945, the unit captured the Ludendorff Bridge over the Rhine River at the city of Remagen. The 9th continued its drive into central Germany and by war's end had advanced into Czechoslovakia.