In 1940 McCreery served with the British Expeditionary Force in its disastrous campaign in France. In May 1941 he was sent by Brooke to North Africa to serve as Chief of Staff to AUCHINLECK; however their relationship was stormy and McCreery was dismissed. He returned to serve as ALEXANDER’s Chief of Staff in August 1942 and played a major role in drawing up the plans for the last stages of the Battle of El Alamein.
McCreery went on to a successful career as a Corps Commander with the X Corps of the 8th Army, which he led in the Salerno landings. The Corps played a crucial role in the Battle for Monte Cassino and McCreery was promoted in November 1944 to lead the 8th Army in its final offensive in Italy.