Kammala wannan jumla: Grindlay ya shiga daga Boonville a ranar 8 ga Satumba, 1862 don tsawon shekaru uku na hidima a cikin Sojojin Tarayya. Ya shiga Kamfanin D na 146th New York Infantry a matsayin kyaftin. A watan Mayu da Yuni na 1864 rundunar ta shiga cikin Janar Ulysses S. Grant na Kamfen na Overland a Virginia. A yakin Basasa a makon farko na watan Mayu, 146th ya yi mummunan rauni. Dukansu kwamandan kwamandan da na biyu a cikin kwamandan sun mutu a cikin aikin, suna barin Grindlay a matsayin babban jami'in. Ya dauki umurnin rundunar kuma ya jagoranci ta ta hanyar yakin Spotsylvania Court House wanda ya biyo baya. An ci gaba da shi zuwa manyan, Grindlay ya jagoranci 146th don sauran yakin, ciki har da yakin Arewa Anna,
Kogin Totopotomoy, da kuma Cold Harbor.