Excellent bifunctional oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) activity and rapid mass transport capability are two important parameters of electrocatalysts for high-performance rechargeable Zn–air batteries (ZABs). Herein, an efficient atomic modulation and structure design to promote bifunctional activity and mass transport kinetics of an ORR/OER electrocatalyst are reported. Specifically, atomic Fe−N4 moieties are immobilized on premade hollow carbon fibers with encapsulated Ni nanoparticles (Fe-N@Ni-HCFs). Synchrotron X-ray absorption spectroscopy and spherical aberration-corrected electron microscope analyses confirm the atomic distribution of the active sites and unique lung bubble-like hollow architecture of the catalyst, while theoretical investigations reveal that the encapsulated Ni nanoparticles can induce electron distribution of the atomic Fe−N4 moieties to reduce reaction energy barriers. As a result, the prepared catalyst possesses enhanced bifunctional ORR/OER activity and well-constructed gas–solid–liquid interfaces for improved mass transfer. These synergetic advantages endow the binder-free Fe-N@Ni-HCFs electrode with the remarkable power density and cycling stability for ZABs, outperforming the commercial Pt/C+Ir/C benchmark. This exceptional performance suggests that the proposed strategy can be extended to the design and fabrication of electrocatalysts for energy conversion and storage.