After Antietam, Ewing was placed on sick leave because of chronic dysentery, and was promoted to Brigadier General on November 29, 1862. He transferred West and served throughout the campaign before Vicksburg, leading the assaults made by General Sherman; and upon its fall was placed in command of a division in the XVI Corps. At Chattanooga, he was given command of the 4th Division of the XV Corps, which formed the advance of Sherman's army and carried Missionary Ridge. Prior to the Battle of Chattanooga, Ewing's command led a diversionary raid that resulted in the destruction of the Empire State Iron Works in Dade County, Georgia, which was being refurbished to increase the South's manufacturing capability. Sherman considered Ewing his most reliable division commander.