An advanced protocol for the intramolecular C–H amination of alkyl groups via amidyl radicals (Hofmann–Löffler reaction) under homogeneous iodine catalysis is reported. This protocol employs common mCPBA as terminal oxidant. It proceeds under mild conditions, with complete chemoselectivity, is compatible with radical intermediates, and allows for the selective intramolecular amination reaction of secondary and tertiary hydrocarbon bonds and is not restricted to benzylic C–H amination. The involvement of an iodine(III) catalyst state in the C–N bond formation derives from selective oxidation at the stage of the corresponding alkyl iodide with mCPBA. Its formation is corroborated by quantum-chemical calculations. This new catalysis thus proceeds within a defined iodine(I/III) catalysis manifold.