The 40th Tank Battalion entered combat on 15 August 1944 fighting across northern France into Belgium, where it made a significant contribution to the defeat of German forces at St. Vith during the Battle of the Bulge.

The 40th Tank Battalion received participation credit for four European campaigns from Northern France to Central Europe and was awarded the Belgian Fourragere.

On 15 October 1957, the 40th and 709th Tank Battalions, as well as Troop E, 87th Cavalry Reconnaissance Squadron, were combined to form the 40th Armor under the Combat Arms Regimental System.

The 1st Squadron was assigned to the 4th Brigade Combat Team (Airborne), 25th Infantry Division and activated on 16 October 2005 at Joint Base Elmendorf-Richardson, Alaska.

The 1-40 Cavalry Regiment conducted 14 months of counterinsurgency operation throughout Southern Baghdad including leading a decisive effort during the Iraq troop surge of 2007.

In December 2011, 1st Squadron (Airborne), 40th Cavalry Regiment deployed back to Paktia and Khost Provinces in Afghanistan in support of Operation Enduring Freedom.