The search for earth abundant, highly active, and robust electrocatalysts is central to the wide spread application of renewable energy conversion technologies. Herein, bulk nitrogen-doped hierarchical structure cobalt carbide, which was composed of nano/micro-particles and coupled with carbon black (denoted as N-Co₂C HS/EC), was developed as a bifunctional oxygen electrocatalyst. N-Co₂C HS/EC exhibited a high half-wave potential of 0.825 V for the oxygen reduction reaction and a low overpotential of 287 mV for the oxygen evolution reaction, both of which were superior to those of precious Pt/C and RuO₂ catalysts. Impressively, a rechargeable zinc–air battery driven by bifunctional N-Co₂C HS/EC delivered a larger peak power density (205 mW cm⁻²), a higher specific capacity (793.08 mW h g_Zn⁻¹), and better rate performance than the one driven by Pt/C + RuO₂ mixture catalysts. Systematic characterization studies and theoretical calculations revealed that the enhanced oxygen electrocatalysis of N-Co₂C HS/EC was attributed to the increased amount of active Co–N_x moieties and the tailored electronic structure due to nitrogen doping. Moreover, the integrated microrod/sheet array benefited the electrocatalytic stability and electron/mass transmission. This work proposed an in situ nitrogen-doping strategy to substantially boost the electrocatalytic performance of metal carbides, which may inspire more effort for developing efficient metal compound electrocatalysts for energy conversion.