Kammala wannan jumla: A farkon yakin basasar Amurka, Sedgwick yana aiki a matsayin colonel kuma mataimakin babban mai binciken Ma'aikatar Sojoji na Washington. Ya rasa aikin farko na yaki a yakin farko na Bull Run, yana murmurewa daga cutar kwalara. An gabatar da shi ga brigadier janar a ranar 31 ga watan Agusta, 1861, ya umurci brigade na 2 na Maj. Janar Samuel P. Heintzelman a cikin rundunar Sojojin Potomac, sa'an nan kuma ya zama kansa, wanda aka sanya shi a matsayin rukuni na biyu na II Corps don Kamfen na Peninsula. A Virginia, ya yi yaƙi a Yorktown da
Bakwai Bakwai. A lokacin Yakin Kwanaki Bakwai, rukunin Sedgwick ya yi yaƙi a tashar Savage da Glendale, an ji rauni a cikin wasan karshe. Bayan Yaƙin Kwanaki Bakwai, an daukaka shi zuwa Manjo Janar. II Corps da kuma rabuwa na Sedgwick ba su shiga cikin yakin Arewacin Virginia ba.