Tuhia he tohutoro mō tēnei wāhanga - I puta a Catlin i te Whare Wānanga o te Ope Taua kotahi marama i muri i te pakarutanga o te Pakanga Tuatahi o te Ao. I muri mai, i whakanohoia ia hei rangatira mo te puni whakangungu o waho o te moana i Quantico, Virginia. I te Oketopa 1917, i tukuna a Catlin ki Parani hei rangatira rangatira mo te 6th Marines. Mai i te 1 ki te 6 o Hune 1918, i kite te 6th Regiment i nga mahi i nga raina o mua mai i Paris-Metz Road na Lucy-le-Bocage ki Hill 142. I te 6 o Pipiri 1918, me tana ope taua e whakaeke ana i a Bois de Belleau
I werohia ia ki te uma e tētahi kaipatu, ā, i kawea ki te hōhipera i te rā i muri mai. Ko te wā tuatahi i whara ai ia i roto i ngā tau 28 o tana mahi.