Ka kammala wannan magana: Bayan ya gama karatunsa, Matthews ya fara aiki a Fort Huachuca a Arizona. A wannan lokacin, sojojin suna amfani da 'yan asalin ƙasar Amirka a matsayin jagora a yammacin Amurka. A lokacin da yake aiki a jihar, an dauke shi a matsayin mai harbi mai kyau. Na gaba, ya shiga Janar John J. Pershing na
yaƙin neman zaɓe zuwa Mexico a 1916 don farautar Pancho Villa. Kodayake Matthews ya yarda cewa bai taba saduwa da Villa ba, zai yi iƙirarin cewa "Na san inda yake". A lokacin yakin duniya na farko, fagen fama na Turai ba su da kyau ga sojan doki; Rundunar ta 10 ta yi aiki a kan iyaka da Mexico, ciki har da rikice-rikice da Mexicans da masu ba da shawara na Jamus a kusa da Nogales, Arizona.