Kammala jumla mai zuwa: A matsayin kyaftin na 'yan sa kai na Connecticut na goma sha biyu, De Forest ya ga aikin a yakin basasa a Louisiana a 1862 da kuma a cikin
Shenendoah Valley yaƙin neman zaɓe a 1864 kafin a sallame shi saboda matsalolin lafiya. Ya wallafa "Miss Ravenel's Conversion daga Secession zuwa Aminci" a 1867 a matsayin zargi na bautar da jama'ar Kudu.