He graduated from the University of Georgia (UGA) in Athens in 1855 with a Bachelor of Arts (A.B.

During the American Civil War, Barnes served as a second lieutenant and major brevet in the Confederate States Army as a member of the Washington Light Artillery Company.

In 1884, Barnes was elected as a Democrat to the 49th United States Congress as the Representative for Georgia's 10th congressional district.

He was re-elected to that position for two additional terms before losing his bid for reelection in 1890.

Barnes was a UGA trustee for the last two years of his life before dying in Augusta on October 24, 1901.