Griff King was a former prison inmate serving out his parole on the Ponderosa. His character was rather hurriedly added in the fourth episode of what would turn out to be the final season - and not even a full season at that. Dan Blocker's death left a gap that the producers tried unsuccessfully to fill with the addition of Griff and the return of David Canary as Candy. What little backstory was given on Griff is mainly in his first two episodes "Riot!" and "New Man" with a few minor additions in "The Witness" "The Sound of Loneliness" and "The Marriage of Theodore Duffy." Had the series continued for another season or two, it's likely Griff would have had long lost relatives, friends and enemies coming out of the woodwork. Although his lack of backstory can be attributed to the speed with which his character was constructed, it was also the practice of television writers not to lock characters into too definite a family history. As shown by the appearance of the occasional Cartwright half-brother, cousin, etc., it's always convenient to give writers the option of writing into an episode a character who has some kind of emotional hold on a featured player.
In 1969, Matheson joined the cast of NBC's western series, The Virginian (1962), in its eighth season, as "Jim Horn". During the final season of the television western Bonanza (1959) in 1972-1973, Matheson played "Griff King", a parolee who tries to reform his life as a worker at the Ponderosa Ranch under Ben Cartwright's watch. Following that, he portrayed young motorcycle cop "Phil Sweet", in the 1973 film, Magnum Force (1973).

