Whakaotihia te rerenga e whai ake nei: I te tau 1861, i te tīmatanga o te Pakanga ā-Iwi o Amerika, ko ia te Kaihauturu o te Rōpū Tuatoru. I muri tata mai, ka wehe ia ki te whakauru atu ki nga kaimahi o te General Edwin Vose Sumner hei "aide-de-camp" matua, ka eke ki te taumata o te Pirimia. He mema ia o te Ope o te Potomac i uru ki nga pakanga o Yorktown, Williamsburg, Fair Oaks, Seven Pines, Savage's Station, Glendale, Malvern Hill, Antietam, Fredericksburg (i puta katoa i te tau 1862), me
Ko te Mine Run i roa mai i te Whiringa-a-rangi 1863 tae noa ki Tihema 1863.