 Ramba uchinyora ndima iyi - Akakwidziridzwa kuva brigadier general wevazvipiri veU.S., kutanga musi waNovember 29, 1862. Pamberi pechirongwa cheChancellorsville, akabviswa pabasa neArmy of the Potomac ndokuiswa kuzvidziviriro zveWashington kwaakadzokera pachigaro chake muCongress. Pashure peGettysburg, Marston akarayirwa kuti agadzire musasa wevasungwa muMaryland, uyo wakazozivikanwa sePoint Lookout. Nzvimbo yacho yakasarudzwa kuti ive Dunhu reSaint Mary pasi pehutungamiriri hwese hwaMajor General Benjamin Butler. Muna 1864, akatungamirira brigade mu Maj. Gen. W.F. Baldy Smiths XVIII Corps panguva yeBermuda Hundred Campaign. Akatora rutivi mukurwiswa kwakaipisisa paCold Harbor, uko bhirigedhi rake rakarasikirwa zvikuru. Munguva yekurwiswa kweUnion kuPetersburg, Gilman akatora kutungamira kwe1st Division muXVIII Corps pazuva rekupedzisira rehondo. Pashure pacho akatungamirira mauto eUnion kurutivi rwokuchamhembe rweRwizi rwaJames nomuzinda wake waiva paFort Pocahontas. Dzimwe nguva akadzokera kunotungamira 1st Division, kusanganisira nguva pfupi panguva yechipiri Hondo yeFair Oaks. Akasarudzwazve kuCongress akasiya basa muna 1865, achibva agamuchira kuonga kwenyika yeNew Hampshire. 