Advancements in zinc–air batteries critically depend on the development of sustainable, high-efficiency electrocatalysts for the oxygen reduction reaction (ORR). In this work, we report a chromium oxide/hydroxide/nitride/carbon@nitrogen-doped reduced graphene oxide nanocomposite (NRGO–N–CrO(OH)–C) as an effective ORR electrocatalyst in alkaline media. Nitrogen-doped reduced graphene oxide (NRGO) was synthesized via an electrochemical method, while chromium oxide–carbon (Cr2O3–C) was prepared using a facile soft-template approach. Subsequent deposition of Cr2O3–C onto NRGO and in situ formation of CrOH/N were achieved through a hydrothermal process. The structural and morphological characteristics of the NRGO–N–CrO(OH)–C nanocomposite were systematically investigated using various microscopy and spectroscopy techniques, confirming the uniform distribution of resulted Cr-based nanostructures on the NRGO sheets. Electrochemical studies demonstrate outstanding ORR activity and durability, with an onset potential of 0.86 V and a half-wave potential of 0.715 V versus RHE, and rotating disk electrode measurements reveal a dominant four-electron ORR pathway. When employed as an air cathode in zinc–air batteries, the NRGO–N–CrO(OH)–C catalyst delivers superior performance compared to commercial noble-metal catalysts, achieving a high open-circuit voltage of 1.48 V, a specific capacity of 665 mA h g−1 and a peak power density of 156 mW cm−2, surpassing the commercial Pt/C catalyst, which has a power density of 134 mW cm−2. Remarkably, the battery exhibits a satisfactory long-term cycling stability over 1680 cycles (280 h) with a coulombic efficiency of 63.8%. These results highlight the NRGO–N–CrO(OH)–C nanocomposite as a cost-effective and high-performance ORR electrocatalyst, offering a promising pathway for advanced zinc–air battery technologies.