Pedzisa mutsara unotevera: Catlin akapedza kudzidza paArmy War College mwedzi mumwe pashure pokunge Hondo Yenyika I yatanga. Gare gare, akaiswa mutarisiri weMarine overseas training camp paQuantico, Virginia. Muna October 1917, Catlin akatumirwa kuFrance semukuru mukuru we6th Marines. Kubvira muna June 1 kusvika muna 6, 1918, 6th Regiment yakaona chiito mumitsara yepamberi kubva kuParis-Metz Road kuburikidza neLucy-le-Bocage kuenda kuHill 142. Musi waJune 6, 1918, neboka rake rokurwisa
Bois de Belleau, akakuvadzwa muchipfuva nomupfuri uye akaendeswa kuchipatara zuva rakatevera racho. Yakanga iri nguva yokutanga yaakanga akuvadzwa mumakore 28 ebasa rinoshingaira.