Rubuta ci gaba ga wannan sakin layi - Yana aiki da doka a Warm Springs, Virginia lokacin da yakin basasar Amurka ya fara. Ya shiga rundunar sojojin tarayya kuma an zabe shi babban jami'in 13 na Virginia Infantry Regiment a watan Mayu 1861. Ya zama colonel na rundunar bayan yakin Chancellorsville a ranar 15 ga Mayu, 1863. A ranar 30 ga Mayu, 1864, an kashe shi a cikin yakin yakin Totopotomoy Creek
ko Battle of Bethesda Church, wanda nan da nan ya gabaci yakin Cold Harbor a lokacin yakin basasa. An riga an zabi Terrill zuwa matsayi na brigadier janar. Majalisar Dattijai ta Tarayya ta tabbatar da nadin a ranar 31 ga Mayu, 1864, don yin matsayi daga Yuni 1, 1864.