Developing noble‐metal‐free bifunctional oxygen electrocatalysts is of great significance for energy conversion and storage systems. Herein, we have developed a transformation method for growing NiMn‐based bimetal–organic framework (NiMn‐MOF) nanosheets on multi‐channel carbon fibers (MCCF) as a bifunctional oxygen electrocatalyst. Owing to the desired components and architecture, the MCCF/NiMn‐MOFs manifest comparable electrocatalytic performance towards oxygen reduction reaction (ORR) with the commercial Pt/C electrocatalyst and superior performance towards oxygen evolution reaction (OER) to the benchmark RuO2 electrocatalyst. X‐ray absorption fine structure (XAFS) spectroscopy and density functional theory (DFT) calculations reveal that the strong synergetic effect of adjacent Ni and Mn nodes within MCCF/NiMn‐MOFs effectively promotes the thermodynamic formation of key *O and *OOH intermediates over active NiO6 centers towards fast ORR and OER kinetics. NiMn‐based bimetal–organic framework nanosheets are successfully grown on multi‐channel carbon fibers (MCCF/NiMn‐MOFs) as a promising bifunctional oxygen electrocatalyst. The strong synergetic effect of bimetallic nodes as well as the well‐designed hierarchical architecture is unraveled to enable MCCF/NiMn‐MOFs with fast kinetics and robust stability towards efficient oxygen electrocatalysis.