In October 1939, a month after the outbreak of the Second World War, Hawkesworth was given command of the 12th Infantry Brigade, taking over from Brigadier George Clark. The brigade was one of three which formed part of the 4th Infantry Division, under Major General Dudley Johnson, and was then serving with the British Expeditionary Force (BEF) in France. However, unlike in the First World War, there was no immediate action and, in late 1939, the brigade moved to the Maginot Line near Metz, where it gained experience engaging the enemy in patrolling actions. He commanded the brigade throughout the Battle of France, finally being forced to retreat to Dunkirk where his brigade was evacuated to England at the end of May 1940, leaving France himself on 1 June. Hawkesworth handed over command of the 12th Brigade on 18 June to Brigadier Daniel Beak and, in August, he was made a Commander of the Order of the British Empire (CBE) and was also mentioned in despatches for his service in France and Belgium. On 9 December 1940 Hawkesworth was promoted to the acting rank of major-general and was appointed Director of Military Training (DMT) at the War Office. In this role he was responsible for general military training for other ranks at a time when the British Army was undergoing a rapid expansion. His rank of major-general was made temporary on 9 December 1941, and, on 25 December 1941, his rank was made permanent.