A fully oxygenated hexagonal 12-layer perovskite BaFeO3 with nominal Fe4+ was obtained by high-pressure synthesis. The structure consists of face-sharing Fe3O9 octahedral trimers and corner-sharing octahedra. A remarkable series of electronic transitions that relieve the electronic instability of Fe4+ are discovered on cooling; 2Fe(4+) -> Fe3+ + Fe5+ charge disproportionation and ordering over two sites accompanied by a structural distortion at 500 K; charge disproportionation of the remaining Fe4+ with magnetic order at 280 K; and an unprecedented charge interchange where Fe3+ and Fe5+ states are exchanged between two sites with spin orientation change at 50 K. These properties demonstrate the presence of multiple competing ground states in this complex, highly condensed network of corner- and face-sharing octahedra.