 Nyora kupfuurira kweiyi ndima - Grigsby akaberekerwa muRockbridge County, Virginia. Akaenda kuWashington College yakazotevera, Washington Lee University. Akava murimi uye akashanda muHondo yeMexico. Apo Hondo yeVanhu yakatanga, akava mukuru mu27th Virginia Infantry muStonewall Brigade muna 1861 uye lieutenant colonel gare gare gore iroro. Pashure pokunge mutungamiriri wehondo, Colonel John Echols, akuvadzwa paKernstownMusi waMarch 23, 1862, Grigsby akatungamira uye akatungamira hurumende yose yakasara yeValley Campaign, Mazuva Manomwe Mazuva, uye Northern Virginia Campaign. Apo Colonel William Baylor, mutungamiri weStonewall Brigade, akaurayiwa paSecond Bull Run, Grigsby akatora brigade. 