Tuhia he tomokanga mō tēnei wāhanga - He tau 1915 i puta mai i te Royal Military College, Sandhurst, i whakawhiwhia a Dempsey hei tuarua tuarua i te Royal Berkshire Regiment. I a ia he rangatira rangatahi, i whawhai ia i te Runga Hauauru i te Pakanga Tuatahi o te Ao, i whara ai ia, a i whakawhiwhia ki a ia te Karauna Hauora. I muri i te pakanga i mahi ia i Iraq i te wa o te tutu o Iraqi o te tau 1920
, Iran i te Pakanga o Rūhia, me Inia.