The development of highly efficient and cost-effective oxygen evolution reaction (OER) electrocatalysts for renewable energy systems is vitally essential. Modulation of the electronic structure through heteroatom doping is considered as one of the most potential strategies to boost OER performances. Herein, a rational design of Mn-doped NiFe layered double hydroxide/reduced graphene oxide (Mn-NiFe LDH/rGO) is demonstrated by a facile hydrothermal approach, which exhibits outstanding OER activity and durability. Experimental results and density functional theory (DFT) calculations manifest that the introduction of Mn can reprogram the electronic structure of surface active sites and alter the intermediate adsorption energy, consequently reducing the potential limiting activation energy for OER. Specifically, the optimal Mn-NiFe LDH/rGO composite shows an enhanced OER performance with an ultralow overpotential of 240 mV@10 mA cm, Tafel slope of 40.0 mV dec and excellent stability. Such superior OER activity is comparable to those of the recently reported state-of-the-art OER catalysts. This work presents an advanced strategy for designing electrocatalysts with high activity and low cost for energy conversion applications.