The direct replacement of sp3 C−H bonds with simple amine units (−NH2) remains synthetically challenging, although primary aliphatic amines are ubiquitous in medicinal chemistry and natural product synthesis. We report a mild and selective protocol for preparing primary and secondary aliphatic amines in a single pot, based on intermolecular sp3 C−H imination. The first C−H imination of diverse alkanes, this method shows useful site‐selectivity within substrates bearing multiple sp3 C−H bonds. Furthermore, this reaction tolerates polar functional groups relevant for complex molecule synthesis, highlighted in the synthesis of amine pharmaceuticals and amination of natural products. We characterize a unique C−H imination mechanism based on radical rebound to an iminyl radical, supported by kinetic isotope effects, stereoablation, resubmission, and computational modeling. This work constitutes a selective method for complex amine synthesis and a new mechanistic platform for C−H amination. [ABSTRACT FROM AUTHOR]