A well-structured magnetic CuFeS2/ZIF-67 hybrid catalyst was synthesized by embedding CuFeS2 nanoparticles into a ZIF-67 framework for efficient peroxymonosulfate (PMS) activation and ultrafast dye degradation. The redox-rich Cu─Fe─Co interface promotes rapid electron transfer and continuous PMS activation, resulting in outstanding catalytic performance. Under optimized conditions (catalyst 75 mg L−1, PMS 125 mg L−1, dye 80 mg L−1, pH 6.4, and 20°C), the optimized 0.4-CuFeS2/ZIF-67 composite achieved 98.06% removal of Reactive Brilliant Blue KN-R (anthraquinone-based anionic reactive dye) within 0.5 min, following pseudo-first-order kinetics with a high rate constant (kobs = 7.49 min−1). Electron paramagnetic resonance and quenching experiments confirmed the coexistence of radical species (SO4•−, •OH, and O2•−) and a non-radical pathway involving 1O2, with singlet oxygen identified as the dominant oxidant. The enhanced activity originates from the synergistic Cu+/Cu2+, Fe2+/Fe3+, and Co2+/Co3+ redox cycling, while sulfur species (S2−/S22−) act as electron mediators that promote charge transfer and stabilize active sites during PMS activation. The catalyst retained over 83% activity after repeated cycles with negligible metal leaching (Cu 0.010 mg L−1, Fe 0.033 mg L−1, Co 0.09 mg L−1). Significant total organic carbon removal (52.81%) demonstrates effective mineralization, highlighting its potential for sustainable wastewater treatment applications.