Initially, Keifer would be commissioned major of the 3rd Ohio Volunteer Infantry. A 3 month regiment, the 3rd Ohio would serve in Western Virginia fighting in the battles of both Rich Mountain and Cheat Mountain after which Keifer was promoted to lieutenant colonel of the regiment. When the regiments term expired, Keifer was then commissioned colonel of the 110th Ohio Volunteer Infantry. Fighting in the Eastern Theater, his regiment would see action at the Second Battle of Winchester. While the Union army was soundly defeated and most of it surrendered, Keifer’s regiment was able to avoid capture. Following the Battle of Gettysburg, Keifer was assigned to brigade command in the III Corps and fought at the Battle of Wapping Heights. As Robert E. Lee’s army retreated to safety in Virginia, Keifer and his regiment were dispatched to New York City to help suppress the draft riots. Joseph returned to the Army of the Potomac in time for the Overland Campaign where he was wounded in the arm at the Wilderness, putting him out of action for a time. When he did return to active duty he was placed in command of the 2nd Brigade, 3rd Division of the VI Corps. He led his brigade at the battles of Winchester and Fisher’s Hill. During the Battle of Cedar Creek, VI Corps commander Horatio Wright temporarily commanded the Army of the Shenandoah and Ricketts temporarily in command of the corps. This put Keifer in command of the 3rd Division in Ricketts’s absence. When Sheridan heroically returned to command the army in the midst of the battle, returning Wright to corps command, Ricketts had already been wounded, leaving Keifer in command of the division for the rest of the battle. For his service during the Shenandoah Valley Campaign, on December 12, 1864, Lincoln nominated Keifer for appointment to the grade of brevet brigadier general of volunteers, to rank from October 19, 1864, which was confirmed on February 14, 1865. When the VI Corps returned to the Army of the Potomac General Seymour was placed in command of the 3rd Division and Keifer returned to command the 2nd Brigade, taking part in the Petersburg fight and the Appomattox Campaign. He would be breveted as a major general, to rank from April 9, 1865, in recognition of his contributions to the campaign. Very nice view of colonel, shown wearing a Lincoln mourning ribbon pinned to the sleeve. Back marked out of Cincinnati.