Career
Harmon was a very prolific bit actor. His career spanned over six decades and almost 300 movie and television roles in a wide variety of genres. Many of his earlier appearances are uncredited.
His first major screen cr was in.
His movie career highlights were roles in Gallant Bess, The Monster of Piedras Blancas, Live Fast, Die Young and The Street is my Beat. The movie in which he made his last screen appearance, The Naked Monster, was released 20 years after his death.
Harmon"s most notable television roles were in Bonanza, Perry Mason (as a police fingerprint/ballistics expert), Star Trek (in the episode "The City on the Edge of Forever"), and The Rifleman (as the hotel clerk Eddie Halstead). In his later years, Harmon became a used books dealer in Los Los Angeles
He collected first editions of Mark Twain.
He suffered a stroke about a year before he died from heart failure.