Stephen Manley is best known for playing Young Spock at seventeen in Star Trek III: The Search for Spock. And more recently he has played in a wide variety of movies and television shows in the years since.
But one of his earlier roles was as Marco Gambini, in the episode Gambini the Great in season eight of Little House on the Prairie.
He also appeared in many other shows and movies prior to this Little House on the Prairie episode as a child and teenage actor too.