Small‐molecule catalysts as mimics of biological systems illustrate the chemists’ attempts at emulating the tantalizing abilities displayed by nature's metalloenzymes. Among these innate behaviors, spin multistate reactivity is used by biological systems as it offers thermodynamic leverage towards challenging chemical reactivity but this concept is difficult to translate into the realm of synthetic organometallic catalysis. Here, we report a rare example of molecular spin catalysis involving multistate reactivity in a small‐molecule biomimetic copper catalyst applied to aziridination. This behavior is supported by spin state flexibility enabled by the redox‐active ligand. Putting a (molecular) spin on copper catalysis: Metalloenzymes routinely perform multielectronic transformations using multistate reactivity and redox cofactors but this behavior is difficult to emulate in synthetic systems. We report a rare example of molecular spin catalysis in the context of copper‐catalyzed aziridination. The molecular spin fluxionality enabled by the redox‐active ligands is central to this behavior.