Development of an efficient and durable water splitting electrocatalyst holds a great commitment for the future energy devices. The real application of oxygen evolution reaction (OER) catalysts mainly suffers from sluggish kinetics and high overpotential except for the Ir and Ru‐based systems. However, the high cost and vulnerability of the Ir and Ru metals are the main hostiles to use them for marketization. Herein, a high‐performance OER electrocatalyst consisting of NiCo alloy nanoparticles supported on high surface area N‐doped porous graphene (NiCo/pNGr(75:25)) is reported. The importance of the doped‐N for achieving the uniform dispersion‐cum‐effective interaction of the size controlled NiCo alloy nanoparticles has been explicitly investigated by transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman, density functional theory (DFT) calculations, etc. The electrochemical analysis of NiCo/pNGr(75:25) shows an overpotential of ≈260 mV at 10 mA cm⁻² with a smaller Tafel slope of ≈87 mV dec⁻¹ and long catalytic durability. DFT calculations are done to check the interaction between the NiCo alloy nanoparticles and the defective sites of pNGr and also with the doped‐N, which could be attained for maintaining long catalytic durability. Furthermore, NiCo/pNGr(75:25) is used as an OER catalyst to fabricate an electrolyzer, which works at very low potential of 1.5 V in 1 m KOH.