Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) bifunctional electrocatalysts are essential for rechargeable zinc-air batteries. Here, a novel design strategy is demonstrated for developing highly dispersed Fe2Ni2N/Co trimetallic nitride nanocrystals strongly coupled with N-doped carbon nanotubes (Fe2Ni2N/Co@NCNT). This unique hybrid catalyst exhibits superior electrocatalytic activity and stability toward both ORR and OER over most reported non-noble metal catalysts. The resulting zinc-air battery shows an impressively small charge–discharge voltage gap of 83 mV at 20 mA cm−2, as well as ultra-long cycling stability even exceeding 850 cycles (850 h) at 5 mA cm−2. Notably, we followed the changes of interatomic distance and local coordination of FeFe and FeN bonds, using in situ XAFS to investigate the origins of the excellent structural stabilities of the Fe2Ni2N/Co@NCNT catalysts during electrocatalysis.