A photoredox-mediated Minisci C–H alkylation reaction of N-heteroarenes with alkyl boronic acids is reported. A broad range of primary and secondary alkyl groups can be efficiently incorporated into various N-heteroarenes using [Ru(bpy)₃]Cl₂ as photocatalyst and acetoxybenziodoxole as oxidant under mild conditions. The reaction exhibits excellent substrate scope and functional group tolerance, and offers a broadly applicable method for late-stage functionalization of complex substrates. Mechanistic experiments and computational studies suggest that an intramolecularly stabilized ortho-iodobenzoyloxy radical intermediate might play a key role in this reaction system.