During the Second World War Howard-Dobson was commissioned as a second lieutenant into the Yorkshire Hussars in 1941. He saw action as a tank troop commander in the 7th Queen's Own Hussars, to which he was transferred, during the long withdrawal from Rangoon in Burma during the early stages of the Burma Campaign. The regiment formed part of the 7th Armoured Brigade, and, after serving in India, Iraq, Palestine, Syria, and Egypt, landed in Italy in early May 1944. Howard-Dobson, along with the rest of the brigade, were to remain there for the rest of the war, engaged in the fighting on the Italian Front. He again saw action during the fourth and final Battle of Monte Cassino, and later, while attached to Lieutenant General Władysław Anders's Polish II Corps, at the Battle of Ancona, the fighting on the Gothic Line and, in April 1945, at the Spring 1945 offensive in Italy, which brought an end to the war in Italy. For his distinguished services in the war he was awarded the Italian Virtuti Militari and the US Silver Star.