We describe cooperative bimetallic catalysis that enables regio‐/stereodivergent asymmetric α‐allylations of aldimine esters. By employing Et3B as the key activator, racemic allylic alcohols can be directly ionized to form Pd or Ir‐π‐allyl species in the presence of achiral Pd or chiral Ir complexes, respectively. The less or more substituted allylic termini of the metal‐π‐allyl species are amenable to nucleophilic attack by the chiral Cu‐azomethine ylide, the formation of which is simultaneously facilitated by Et3B, affording α‐quaternary α‐amino acids with high regioselectivity and excellent stereoselectivity. The use of readily available allylic alcohols as electrophilic precursors represents an improvement from an environmental and atom/step economy perspective. Computational mechanistic studies reveal the crucial role of the Et3B additive and the origins of stereo‐ and regioselectivities by analyzing steric effects, dispersion interactions, and frontier orbital population. The regio‐ and stereodivergent asymmetric α‐allylation of aldimine esters with racemic allylic alcohols was enabled by cooperative catalysis. The Et3B additive plays a significant role in ionizing allylic alcohols to form electrophilic metal‐π‐allyl species and simultaneously promotes the formation of nucleophilic Cu‐ylides. Computational mechanistic studies revealed the role of the Et3B additive and the origins of stereo‐ and regioselectivities.