Kammala jumla mai zuwa: Hayes kuma ya yi aiki a cikin soja a cikin Yakin Mutanen Espanya-Amurka, Philippine-American War da yakin duniya na farko. Ya kasance memba na Rundunar Cleveland ta Farko, daga baya aka sani da Troop A na Ohio National Guard. A lokacin Yakin Spain-Amurka, an nada shi babban jami'in a cikin Sojan doki na farko na Ohio. Ya yi yaƙi a Santiago de Cuba Campaign, lokacin da aka ji masa rauni yayin tsallaka Kogin San Juan da
kai hari kan San Juan Hill, kuma daga baya a mamaye Puerto Rico.