Whakaotihia te rerenga e whai ake nei: I te marama o Akuhata 1917, i whakatairangahia a Gatley ki te rangatira rangatira o te 55th Field Artillery Brigade, he waahanga o te 30th Division. I muri mai ka whakawhiti ia ki te whakahau i te 67th Field Artillery Brigade o te 42nd Division, i arahina e ia tae noa ki te mutunga o te pakanga. I whai wāhi ia ki te
Champagne-Marne, Aisne-Marne, St. Mihiel, me Meuse-Argonne nga pakanga me nga whakaeke. Mai i te Hakihea 1917 ki te Hanuere 1918, ko Gatley te rangatira o te 30th Division. I te tau 1919 i whakahau ia i te 42nd Division i te wa o tana mahi mahi i muri i te pakanga i Tiamana.