Born in Bath, Somerset, in 1911, Hill was educated at Marlborough College and the Royal Military College, Sandhurst before joining the British Army in 1931 and being commissioned into the Royal Fusiliers. He commanded a platoon for a short period, and was then attached to the command post of Field Marshal Lord Gort during the Battle of France in May 1940, where he oversaw the evacuation of Brussels as well as the beach at De Panne during the evacuation of Dunkirk. After a brief period of time in the Irish Free State, he volunteered for parachute training and joined the 1st Parachute Battalion, and was its commanding officer when its parent formation, the 1st Parachute Brigade, was deployed to North Africa.