This is the only time Bobby Vinton appears in the show and one of only a handful of acting credits. He is perhaps best known for his singing career, being a teen idol in the early and mid 60s for such hits as "Roses Are Red," "Blue Velvet," and "Mr. Lonely." From here he would go on to host his own variety show in the 70s: The Bobby Vinton Show (1975).
This is the second of three appearances Ralph Bell makes in the series and the first of two appearances wherein he plays William Smathers, Martin's newspaper publisher. He plays a doctor in his first appearance, i.e. in Double Date (1963), and repeats his Smathers role in Cathy, the Rebel (1965).
Newpaper publisher William Smathers, played here by Ralph Bell, is a season two replacement for J.R. Castle, played by John McGiver, who appears a total of five times and only in season one.