In the Chancellorsville Campaign, Newton was wounded at Salem Church. At Gettysburg, George Meade named Newton to command of the I Corps after John F. Reynolds was killed in the battle. Command of the corps had fallen to Abner Doubleday, the ranking division commander, but Meade had little regard for Doubleday's fighting ability, dating back to South Mountain, so Meade preferred Newton to command it instead. Newton commanded the I Corps until the start of the Overland Campaign in the spring of 1864, when the I Corps was dissolved and its remnants divided among the II and V Corps. At this point, Newton reverted to the rank of brigadier general and was sent west to serve with William T. Sherman.