As CIGS, Brooke was the functional head of the British Army, and as chairman of the Chiefs of Staff Committee, which he dominated by force of intellect and personality, he took the leading military part in the overall strategic direction of the British war effort.
Som CIGS var Brooke hærens øverste leder, og som formand for stabschefernes komite, som han dominerede med sit intellekt og personlighed, tog han den militære hovedrolle i den overordnede strategiske styring af krigen.