This study investigates the effect of intrinsic magnetic order on electrochemical water splitting, focusing on the role of magnetic order in enhancing oxygen evolution reaction (OER) activity. The research uses epitaxial La0.67Sr0.33MnO3 thin films as model catalysts, which can be tuned from ferromagnetic to paramagnetic by changing the temperature during water electrolysis. The results show that ferromagnetic ordering below the Curie temperature enhances OER activity, and that the application of an external magnetic field further increases the current density. The magnetic anisotropy of the catalyst film is found to correlate with the external magnetic field-induced OER enhancement. The study also reveals that the OER enhancement is connected to the magnetic order of the bulk catalyst, rather than lateral long-range order in the surface layer. The findings suggest that both the intrinsic magnetic order in La0.67Sr0.33MnO3 films and the alignment of magnetic domains upon external field exposure increase catalytic activity. The results support the hypothesis that spin-polarized orbital configurations in ferromagnetic bonds enhance OER efficiency by promoting the generation of triplet oxygen through quantum spin-exchange interactions and intrinsic spin filtering. The study also highlights the importance of magnetic order in catalytic activity, showing that the presence of ferromagnetic ordering below the Curie temperature enhances OER activity. The research provides a unifying picture for the spin-polarized enhancement in magnetic oxide catalysts, demonstrating that the intrinsic magnetic order and magnetic domain alignment are key factors in enhancing catalytic activity. The findings have implications for the design of efficient electrocatalysts for green hydrogen production.This study investigates the effect of intrinsic magnetic order on electrochemical water splitting, focusing on the role of magnetic order in enhancing oxygen evolution reaction (OER) activity. The research uses epitaxial La0.67Sr0.33MnO3 thin films as model catalysts, which can be tuned from ferromagnetic to paramagnetic by changing the temperature during water electrolysis. The results show that ferromagnetic ordering below the Curie temperature enhances OER activity, and that the application of an external magnetic field further increases the current density. The magnetic anisotropy of the catalyst film is found to correlate with the external magnetic field-induced OER enhancement. The study also reveals that the OER enhancement is connected to the magnetic order of the bulk catalyst, rather than lateral long-range order in the surface layer. The findings suggest that both the intrinsic magnetic order in La0.67Sr0.33MnO3 films and the alignment of magnetic domains upon external field exposure increase catalytic activity. The results support the hypothesis that spin-polarized orbital configurations in ferromagnetic bonds enhance OER efficiency by promoting the generation of triplet oxygen through quantum spin-exchange interactions and intrinsic spin filtering. The study also highlights the importance of magnetic order in catalytic activity, showing that the presence of ferromagnetic ordering below the Curie temperature enhances OER activity. The research provides a unifying picture for the spin-polarized enhancement in magnetic oxide catalysts, demonstrating that the intrinsic magnetic order and magnetic domain alignment are key factors in enhancing catalytic activity. The findings have implications for the design of efficient electrocatalysts for green hydrogen production.