Rubuta ci gaba don wannan sakin layi - Wani digiri na 1915 na Kwalejin Soja na Royal, Sandhurst, Dempsey an ba shi izini a matsayin na biyu a cikin Royal Berkshire Regiment. A matsayinsa na ƙaramin jami'i, ya yi yaƙi a Yammacin Yammacin lokacin Yaƙin Duniya na Farko, inda aka ji masa rauni, kuma an ba shi lambar yabo ta Soja. Bayan yakin ya yi aiki a Iraki a lokacin juyin juya halin Iraqi na 1920
, Iran a lokacin yakin basasa na Rasha, da kuma Indiya.