I le aso 1 Iulai 1863, na siitia ai Walker i le tulaga o le brigadier general ma ina ua maeʻa le Gettysburg campaign, na tofia ai o ia i le Major General Henry Heth's division o le III Corps o le Army of Northern Virginia, na muamua faʻatonuina le Heth's brigade, ona faʻatonuina ai lea o le Brigadier General James J. Archer's brigade, ina ua maeʻa le manuʻa matuia a Archer. Na avea Walker ma ta'ita'i 'au i lalo o le ta'ita'iga a Heth, se'ia oo ina leiloa lona vae agavale i le Taua i Spotsylvania Court House ia Me 10, 1864. Na auai o ia i le Taua i Bristoe Station i le aso 14 o Oketopa, 1863, i le Taua i Mine Run
ma, ina ua uma ona auauna atu i le Vanu o Shenandoah i le taumalulu o le 1864-1864, i le Taua o le Toafa ae leʻi manuʻa i le Maota o le Faamasinoga i Spotsylvania.