Shortly thereafter he was appointed to the rank of colonel as commander of the 138th Regiment Infantry U.S. Colored Troops. He led the regiment from July 1865 to January 6, 1866, when it was mustered out. Later that year, he was appointed a captain in the 7th U.S. Cavalry. Meanwhile, the Senate finally approved awards of brevet ranks to distinguished veterans of the Civil War. Benteen received brevets of major for the Battle of Mine Creek and lieutenant colonel for the Battle of Columbus (1865).