The cyclization of nitrogen-centered radicals is a powerful strategy for accessing N-heterocycles, highly sought-after targets in the pharmaceutical industry. The integration of N-radicals with group-migration chemistry could open new avenues for reaction design. Herein, we present a radical cascade strategy based on visible light-driven photoredox catalysis, which enables rapid construction of arylethylamine motif-containing 1,4,5,6-tetrahydropyridazines via hydrazonyl radical cyclization and subsequent aryl transfer. The catalytic reaction is redox-neutral, exhibits broad functional group compatibility, and enables the construction of diazacycles containing a synthetically challenging all-carbon quaternary center.