 Blamey joined the Australian Army as a regular soldier in 1906, and attended the Staff College at Quetta. During the First World War he participated in the landing at Anzac Cove on 25 April 1915, and served as a staff officer in the Gallipoli Campaign, where he was mentioned in despatches for a daring raid behind enemy lines. He later served on the Western Front, where he distinguished himself in the planning for the Battle of Pozières. He rose to the rank of brigadier general, and served as chief of staff of the Australian Corps under Lieutenant General Sir John Monash, who credited him as a factor in the Corps' success in the Battle of Hamel, the Battle of Amiens and the Battle of the Hindenburg Line.
