Kammala wannan jumla: MacRae ya shiga aikin soja a cikin 'yan bindigar haske na Monroe, kuma an zabe shi kyaftin lokacin da ya zama Kamfanin B, na goma sha biyar na Arewacin Carolina. A watan Afrilun 1862, an daukaka shi zuwa Laftanar Kanar. A lokacin yakin Peninsula da kuma Manassas na biyu, rundunarsa ta kasance wani ɓangare na brigade na Howell Cobb. A yakin Antietam, MacRae ya umurci brigade wanda aka rage zuwa mutane 250 a lokacin yakin a cikin 'yan makonni da suka gabata. Rundunar MacRae ta sake dawo da hare-haren Union guda uku amma ya koma baya lokacin da yake da mutane 50 kawai da suka rage kuma kayan aikinsa na bindigogi ya ƙare. A Fredericksburg ya yi yaƙi tare da rundunarsa a Marye's Heights. Nan da nan bayan yakin da aka yi a Arewacin Carolina an canja shi zuwa Brigadier Janar John Rogers Cooke na brigade na Arewacin Carolina. Cooke ya ji rauni sosai a Fredericksburg kuma ba zai dawo ba har sai Afrilu 1863. A watan Fabrairun 1863, MacRae ya ci gaba da zama colonel. Wannan brigade ya yi aiki a Arewacin Carolina da kudu maso gabashin Virginia har bayan yakin Gettysburg. a watan Fabrairun 1863, colonel, kuma a 1864 an ba shi izinin janar janar. Bayan da ya sake shiga rundunar sojojin Arewacin Virginia, an rarrabe MacRae don ƙarfin hali a yakin Bristoe Station. Bayan da Brigadier Janar William Whedbee Kirkland ya ji rauni a yakin Cold Harbor MacRae an inganta shi na dan lokaci zuwa mukamin brigadier general kuma an sanya shi ga umurnin brigade na Kirkland (wannan shi ne tsohon brigade na Brigadier Janar J. Johnston Pettigrew). A cikin
Ream's Station MacRae's, Lane, da kuma Cooke's brigades sun kori John Gibbon na 2 na Winfield Scott Hancock na II Corps daga garuruwan da ke gaba da su kuma suka kama batirin bindiga. Bayan kyakkyawan aiki a yakin Boydton Plank Road MacRae ya kasance tare da sojojin ta hanyar Appomattox Campaign.