 On January 13, 1866, President Andrew Johnson nominated Long for appointment to the 
brevet grade of major general of volunteers, to rank from March 13, 1865, and the U.S. Senate confirmed the appointment on March 12, 1866.Long was mustered out of the volunteer service on January 15, 1866 On April 10, 1866, President Andrew Johnson nominated Long for appointment to the brevet grade of brigadier general in the Regular Army of the United States, to rank from March 13, 1865, for gallantry at the Battle of Selma, and the U.S. Senate confirmed the appointment on May 4, 1866.On July 17, 1866, President Andrew Johnson nominated Long for appointment to the brevet grade of major general in the Regular Army, to rank from March 13, 1865, for his services during the war, and the U.S. Senate confirmed the appointment on July 23, 1866.