In March 1917 Crooks was promoted to second lieutenant and was awarded the Military Cross for conspicuous gallantry and devotion to duty for his command of a carrying party who supplied the front line with grenades.

Hill 971 was the highest point of the Sari Bair Ridge at Gallipoli.

Crooks was demoted back to sergeant and docked pay after interfering in a dispute among troops, and was eventually sent back to Australia as a disciplinary case after being AWOL (absent without leave) for four days in March 1918.

It was hoped that in capturing Hill 971 and Chunuk Bair Allied forces would secure access across the peninsula and therefore capture the Turkish forts guarding the straits.

Crooks went on to serve in France and Belgium, transferring to the 45th Battalion.