Archer was finally exchanged late in the summer of 1864, and rejoined the army. On August 9, he was ordered to report to the Army of Tennessee under Hood in Atlanta, but this order was revoked ten days later, possibly due to his bad health. Instead, he resumed command of his old brigade, and briefly served in the Siege of Petersburg, until his health finally collapsed after the Battle of Peebles' Farm. He died in Richmond, Virginia on October 24, 1864, and was buried in Hollywood Cemetery.