Kammala wannan jumla: Weber ya shiga yaƙi a cikin Yaƙin basasa a matsayin colonel a ranar 16 ga Mayu, 1861. Ya tayar da wani rukunin Jamus da Amurka da aka sani da "Turner Rifles", wani kamfani wanda daga bisani ya zama wani ɓangare na 20th New York Infantry. Weber ya kasance a Fort Monroe a Virginia. Ya shiga cikin
kamawar Fort Hatteras. Daga watan Satumbar 1861 zuwa Mayu 1862, ya umurci Camp Hamilton, kusa da Fort Monroe, an ba shi izinin janar janar na masu sa kai a ranar 28 ga Afrilu, 1862. Ya kasance a Newport News a lokacin gwagwarmaya tsakanin "Monitor" da "Virginia" a cikin tsammanin wani hari na Confederate daga ƙasa. Ya shiga cikin kama Norfolk, Virginia a watan Mayu, sannan ya yi umurni a Suffolk har zuwa watan Satumba, lokacin da aka umurce shi zuwa rundunar sojojin Potomac inda ya umurci Brigade na Uku, Division na Uku, Rundunar Sojoji na Biyu a cikin Sojojin Potomac.