He played a voice in the Star Wars Radio Drama (1980), and I think The Empire Strikes Back Radio Drama (1981?) by NPR. In Star Wars, he was the voice of a Corellian pilot (BoShek) who was talking to Ben Kenobi.

Ben Kenobi: (Bernard Behrens) I heard that Corellians are among the best pilots in the galaxy.

BoShek: (DAG) You heard right, except that we're not `Among'. We ARE the best.