An unprecedented carbene-catalyzed radical trifluoromethylation of olefins with aldehydes in the presence of Togni reagent was developed, thus providing the β-trifluoromethyl-α-substituted ketones with a broad scope and moderate to high chemical yields. Notably, this process includes a single-electron-transfer process and utilizes the persistent N-heterocyclic-carbene-bound radical as a key intermediate to trigger the cascade radical cross-coupling.