<p>Chiral hydrazines are important building blocks in chiral drug molecules, <i>N</i>-amino peptides, and aza-heterocycles. The catalytic enantioconvergent <i>N</i>-alkylation of readily available hydrazine derivatives with various racemic alkyl halides offers a highly attractive route to chiral hydrazines. However, this process remains challenging due to the lack of efficient asymmetric catalytic systems and the difficulty in achieving regioselectivity at the <i>N</i>¹/<i>N</i>² positions of hydrazine derivatives. Herein, we demonstrate a general copper-catalysed enantioconvergent <i>N</i>-alkylation of hydrazine derivatives with racemic α-haloamides. This strategy provides a modular approach for the synthesis of diverse enantioenriched hydrazines with excellent regio- and enantioselectivity. The key to success lies in the development of a radical-polar crossover nucleophilic substitution process and the employment of suitable hydrazine nucleophiles. Furthermore, this method provides a versatile platform to access a series of enantioenriched aza-heterocycles through facile subsequent transformations. It also enables the stereodivergent synthesis of all four possible stereoisomers of <i>N</i>-amino dipeptides bearing two stereocenters, with excellent stereoselectivity.</p>