Rubuta ci gaba don wannan sakin layi - A lokacin da yake da shekaru 25, Hoffman ya shiga aikin soja don yakin basasa. Bayan ya shiga Philadelphia a ranar 10 ga Agusta, 1861, sai ya shiga cikin wannan rana a matsayin mai zaman kansa tare da Kamfanin E na 72 na Pennsylvania Infantry (wanda aka fi sani da "Fire Zouaves"). An kai shi tare da rundunarsa zuwa Virginia, ya ga aikin a yakin Ball's Bluff (Oktoba 21, 1861), ya shiga cikin ci gaba da sojojin Union na Major-General Nathaniel P. Banks a kan Winchester da Yorktown, kuma ya yi yaƙi a cikin kwanaki bakwai na Seven Pines.
(wanda aka fi sani da Fair Oaks, Mayu 31 zuwa Yuni 1, 1862), Savage's Station (Yuni 29, 1862), da kuma Malvern Hill (Yuli 1, 1862) kafin shiga cikin yaƙe-yaƙe na Antietam (Satumba 17, 1862), Fredericksburg (Disamba 12-15, 1862), da kuma Chancellorsville (Afrilu 30 zuwa Mayu 6, 1863). A ranar 1 ga Oktoba, 1863, an canja shi zuwa Kamfanin 143 na 2nd Battalion, U.S. Veteran Reserve Corps (wanda aka fi sani da marasa lafiya), kuma daga bisani an ba shi kyauta.