Significant progress has been made in platinum group metal (PGM)-free oxygen reduction reaction (ORR) catalysts derived from Fe. However, Fenton chemistry due to the presence of Fe and peroxide in electrodes causes serious degradation of ionomer and membrane, limiting the use of these Fe-based catalysts in proton exchange membrane fuel cells (PEMFCs). Therefore, PGM-free catalysts that are also free of Fe are urgently needed to enable durable and inexpensive PEMFCs. Here, we report a new type of highly dispersed nitrogen-coordinated single-atom Co site catalyst. This catalyst is derived from Co-doped metal-organic frameworks through a one-step controlled thermal activation. A combination of aberration-corrected electron microscopy couple with electron energy loss spectra and X-ray absorption spectroscopy clearly verify the co-location of Co and N at the atomic level in the form of CoN₄. Such a catalyst with properly controlled Co doping content and thermal activation achieved comparable activity to state of the art Fe-based catalysts, showing a respectful half-wave potential of 0.80 V vs. RHE in acids, only 60 mV lower than Pt catalysts (60 mgPt/cm²) in challenging acidic media. Exceptional stability was observed in both potential cycling and constant potential (e.g., 0.7 V) tests. The high ORR performance is attributed to the presence of well-dispersed single CoN₄ active sites embedded in the porous carbon matrix without formation of inactive Co aggregates. Fuel cell tests further confirmed that the intrinsic high ORR activity and stability translate to a high-performance cathode in PEMFCs. This atomic single Co site catalyst is a promising step toward replacement of Fe in PGM-free catalysts for advanced fuel cell technologies.