Combustion systems having reduced nitrogen oxide emissions and methods of using the same are disclosed herein. In one embodiment, a combustion system is provided. The combustion system includes a combustion zone, which includes a burner for converting a fuel, under fuel rich conditions, to a flue gas. An intermediate staged air inlet is downstream from the combustion zone, for supplying intermediate staged air to the flue gas and producing fuel lean conditions. A reburn zone is downstream from the intermediate staged air inlet for receiving the flue gas. A process for using the combustion system and a method of reducing NOX flowing into the reburn zone of a combustion system are also described herein.