Rubuta ci gaba ga wannan sakin layi - Johnson ya shiga cikin rundunar Union a lokacin da yake da shekaru 15. An fara shi ne a kamfanin H na 43rd Ohio Infantry Regiment. An ba da umurni ga rundunar ta XVI Corps a cikin Ƙungiyar ta huɗu, amma a cikin bazara na 1864, an canja Johnson zuwa Ƙungiyar farko na XVII Corps. A can, ya yi aiki a karkashin Janar John W. Sprague. A ranar 1 ga Mayu, 1864, rundunar Johnson ta shiga rundunar Janar William Tecumseh Sherman a Chattanooga. Yakin farko da Johnson ya shiga inda ya kasance a karkashin wuta shi ne yakin Decatur. Johnson ya sami rauni kaɗan a ƙafa, sama da haɗin gwiwa na hagu, a yakin Resaca
Ka yi haƙuri. Johnson har yanzu ya shiga cikin fadace-fadace na gaba, kamar yakin Dallas, yakin Kennesaw Mountain, da yakin Peachtree Creek. Bayan faduwar Atlanta, Johnson ya yi aiki a matsayin mai kula da Janar Sprague, wani matsayi da ya yi aiki har sai an sallame shi a karshen yakin. Bayan yakin, Johnson ya koma Lorain County, Ohio.