Earl Hamner appeared in only one episode of The Waltons,
with the exception of him introducing segments on A Decade
of The Waltons. His one episode was in the first episode of
season 2, "The Journey".
There is a scene in this episode where Maggie McKenzie is
having dinner with John Boy, after he took her to see the ocean
once more before her death. She reminisces of the time when she
was there with her husband on their honeymoon and there is a flashback
sequence where we see a young Maggie dancing with her husband
Michael. The non speaking part of Michael is played by Earl Hamner.
Incidentally have a close look at the photographs which Maggie
shows John Boy in this episode. They are family photos of the
Hamner family. Earl's sister, Marion Hamner, his inspiration for
Mary Ellen, also appeared on an episode of The Waltons.
She appeared briefly in a non speaking role in "The Odyssey".