The　role　of　surface　spin　configuration　in　spin-dependent　catalytic　reactions　remains　contentious,　particularly　when　compared　to　the　established　dominance　of　coordination　environments.　Here,　we　resolve　this　debate　by　systematically　probing　oxygen　reduction　reaction　(ORR)　mechanisms　on　high-index　Ni　single-crystal　facets　([210],　[310],　[520])　through　integrated　density　functional　theory　(DFT)　and　experimental　studies.　Contrary　to　conventional　d-band　center　predictions,　we　demonstrate　that　ferromagnetic　ordering　fundamentally　dictates　catalytic　activity　by　stabilizing　triplet　O2　adsorption　and　lowering　spin-forbidden　transition　barriers.　The　Ni　(210)　facet　exhibits　superior　ORR　performance　(half-wave　potential:　0.842　V　vs.　RHE),　outperforming　Ni　(310)　and　Ni　(520)　due　to　its　optimized　d-band　center　alignment　and　enhanced　saturation　magnetization.　External　magnetic　fields　amplify　this　effect,　yielding　a　28%　current　density　enhancement　for　Ni　(210)—nearly　triple　that　of　Ni　(520).　Spin-polarized　DFT　calculations　reveal　that　ferromagnetic　ordering　reduces　the　potential-determining　step　energy　barrier　for　*OH　desorption　by　7.0%,　overriding　coordination-number　effects.　These　findings　establish　ferromagnetic　alignment　as　a　critical　design　criterion　for　spin-engineered　electrocatalysts,　offering　a　paradigm　shift　from　coordination-centric　optimization　to　spin-polarized　interface　engineering.　©　2025　Wiley-VCH　GmbH.