Actually, the term "New South" was coined in the
1880's by
Henry Grady, then editor of the
Atlanta Constitution, advocating that the
South move away from its
agricultural roots and become an
industrialized region.
During the U.S. Civil War, the industrial nature of the Union hurt the South at least as much as its superior number of soldiers; the Confederacy was superior tactically, but couldn't keep its soldiers in food, shoes, or ammunition. The disparity would have been even more evident had Virginia not joined the CSA; Richmond was the industrial capital of the South (as well as, eventually, political), and its industries (plus foraging) kept C.S. Army standards of living at least at subsistence levels. (The Confederate Army wouldn't have lasted nearly as long as it did anyway, had Virginia not joined and brought General Robert E. Lee with it.) Grady's New South, secession notwithstanding, needed to be able to support itself industrially, rather than having a mercantilistic relationship with the North.
Atlanta was an ideal place to advocate this philosophy, as General William Tecumseh Sherman burned the city to the ground in 1864, and it therefore had to start anew. Unfortunately for the rest of the South, real industrial progress didn't begin until civil rights became a reality, brain drain stopped, and right-to-work laws attracted companies away from states with stronger union movements.