April 1918 he was named commander of the 4th Army, a.k.a. the Army of Monte Grappa. In the Battle of Solstizio his army was able to stop the Austrian offensive. During the Battle of Vittorio Veneto the troops under Giardino's leadership were the first Italian troops to attack the Austrian front in order to force the Austrian general staff to use the reserve troops against the Italians on Monte Grappa, facilitating the attack along the Piave River that took place three days later. After the armistice of Villa Giusti Giardino's 4th was disbanded.