Whakaotihia te rerenga e whai ake nei: I mahi a Rowley hei kaikoroniora o te 13 o Pennsylvania Infantry mai i te Paenga-whāwhā 25, 1861, ki te 6 o Akuhata o taua tau. I muri mai ka riro ia hei koroneela o te 102nd Pennsylvania Volunteer Infantry Regiment. I whara ia i te
Te Pakanga o Seven Pines, i a ia e ārahi ana i tana rerenga i roto i te Ope o Potomac. I arahina e ia (mo te wa poto) tetahi parirau i roto i te VI Corps i te Pakanga o Fredericksburg. I whakatairangahia ia ki te taumata o te brigadier general ki te taumata mai i te Whiringa-a-rangi 29, 1862, ka whakahau a Rowley i tetahi parirau o te I Corps i te Pakanga o Chancellorsville. Ko ia te rangatira o te wehenga tuatoru, I Corps i te timatanga o te Pakanga o Gettysburg, i te wa e mahi ana a Maj. Gen. Abner Doubleday hei rangatira o te ope. (Ko Chapman Biddle i ārahi i te tira a Rowley.) I te Hōngongoi 1, 1863, he nui te mate i pa ki te piritihana i te wehenga a Maj. Gen. Harry Heth. I werohia ia i tana hoiho i te wa o te reti i te wa i mutu ai i te awa. E mate ana i te mate mai i te nui o ngā hua manu i runga i ona waewae o roto, he werawera ia, me te riri. Whai muri i te pakanga i waenga i a Rowley me Brig. Gen. Lysander Cutler mo te whanonga o etahi o nga rangatira o te 7 o Wisconsin, i whakawakia e Cutler nga whakapae mo te haurangi i te Paenga-whawha 1864. I raro iho i te 24 haora ki te whakarite i te whakawakanga mo te whakawakanga, i whakawakia a Rowley e te kooti hoia e kii ana te kaituhi a John F. Krumwiede, "ka kore e whai mana, ka haere ki tana ake pahu". Ahakoa i whakahokia mai e te Minita mo te Pakanga a Edwin M. Stanton me te Perehitini a Aperahama Lincoln, i whakawhiwhia a Rowley ki tetahi rohe anake i te hauauru o Pennsylvania, na te riri tonu i waenga i te rangatira ope taua a George G. Meade me te rangatira o te ope taua a Gouverneur K. Warren. I aukatihia e nga mahi a General Darius N. Couch i te ngana ki te aukati i te whakaekenga o 1864 o Pennsylvania e te Kaihauturu a Jubal Early, i whakarere ia i tana komihana i te Tihema 29, 1864.