Simultaneously enhancing the reaction kinetics, mass transport, and gas release during alkaline hydrogen evolution reaction (HER) is critical to minimizing the reaction polarization resistance, but remains a big challenge. Through rational design of a hierarchical multiheterogeneous three-dimensionally (3D) ordered macroporous MoC-embedded nitrogen-doped carbon with ultrafine Ru nanoclusters anchored on its surface (OMS MoC/NC-Ru), we realize both electronic and morphologic engineering of the catalyst to maximize the electrocatalysis performance. The formed Ru-NC heterostructure shows regulative electronic states and optimized adsorption energy with the intermediate H*, and the MoC-NC heterostructure accelerates the Volmer reaction due to the strong water dissociation ability as confirmed by theoretical calculations. Consequently, superior HER activity in alkaline solution with an extremely low overpotential of 15.5 mV at 10 mA cm with the mass activity more than 17 times higher than that of the benchmark Pt/C, an ultrasmall Tafel slope of 22.7 mV dec, and excellent electrocatalytic durability were achieved, attributing to the enhanced mass transport and favorable gas release process endowed from the unique OMS MoC/NC-Ru structure. By oxidizing OMS MoC/NC-Ru into OMS MoO-RuO catalyst, it can also be applied as efficient oxygen evolution electrocatalyst, enabling the construction of a quasi-symmetric electrolyzer for overall water splitting. Such a device's performance surpassed the state-of-the-art Pt/C || RuO electrolyzer. This study provides instructive guidance for designing 3D-ordered macroporous multicomponent catalysts for efficient catalytic applications.