Ben is best remembered as Frank Smith, Sgt. Joe Friday's sidekick on Dragnet.
He had a major role in All's Quiet on the Western Front. He was a child actor for many years.
As I recall, his final role was as a police desk sergeant on an ABC show whose name I don't remember. Because he had that role/commitment, he was unable to join with Jack Webb in the resurrection of Dragnet ca. 1968, so Webb got Harry Morgan instead.