After Chancellorsville, Buschbeck went on leave, missing the Battle of Gettysburg. (Charles Coster commanded the brigade in his absence.) After returning to the army, he was transferred to the Western Theater, under the command of Maj. Gen. Joseph Hooker. Buschbeck's brigade was present at the Battle of Wauhatchie and the Battle of Missionary Ridge, where it was engaged on the Union left under Maj. Gen. William Tecumseh Sherman in the attack on Tunnel Hill. When XI Corps was combined with XII Corps into the XX Corps under Hooker, Buschbeck was the highest ranking German officer retained in command. He led a brigade under John W. Geary (2nd Brigade, 2nd Division) in the Atlanta Campaign, in action at the Battle of Rocky Face Ridge, the Battle of Resaca, and the Battle of Dallas before being mustered out of the service. Buschbeck's regiment left for Philadelphia on March 25, 1864. Nonetheless, he is listed as brigade commander April 16 to May 22, 1864. Buschbeck served with distinction but never received a promotion, even by brevet, to the rank of brigadier general.