Second Army spent most of the war positioned around the Ypres salient, but was redeployed to Italy as part of the Italian Expeditionary Force between November 1917 and March 1918.

During the operation, American (82nd and 101st), British (1st) and Polish (1st Polish Parachute Brigade) airborne troops, outside the control of Second Army, were landed to capture vital bridges over several rivers in the east of the Netherlands, in order to allow Second Army's XXX Corps to cross the Rhine and advance into Germany, relieving the parachute troops en route.

However, the single road XXX Corps had to traverse caused enormous logistical difficulties and, combined with German counterattacks, the operation failed resulting in the loss of much of the 1st Airborne Division during the Battle of Arnhem.

Second Army spent the rest of 1944 exploiting the salient in the German line that it had created during Operation Market Garden, to advance on the Rhine and Meuse rivers in the Netherlands.

The final part of this advance took place in mid-January 1945, with the clearing of the Roermond Triangle (codename Operation Blackcock) by XII and VIII Corps.

Whilst it pinned down the German forces facing it, the Canadian First Army and US Ninth Army made a pincer movement from north and south (Operations Veritable and Grenade) which pierced the Siegfried Line in that area and cleared the remaining German forces west of the Rhine in conjunction with further American offensives in the south of the Rhineland.

Shortly thereafter, the Second World War in Europe came to an end with the surrender of the government of Karl Dönitz, who had succeeded Adolf Hitler after his suicide.