We demonstrate a robust and generic mechanism, which we term "chaos-assisted channeling," to achieve unidirectional output from wave-chaotic microcavities with long-lived resonances. It utilizes the coexistence of regular and chaotic ray dynamics in most deformed microcavities. Long-lived resonances are formed by total internal reflection on classical periodic orbits, and their leakage into the chaotic region of the phase space is efficiently channeled into an attached waveguide without additional loss. We explain this behavior using a ray dynamics analysis which is confirmed via numerical simulations and experimental demonstration.