"Must be Santa," the song Dylan sang, was written by William Fredericks and Hal Moore and originally recorded by Mitch Miller. Mitch Miller was a music producer, I do believe (let's check Wikipedia), who was most famous for a TV show in the 60s called "Sing Along With Mitch."
I just went to YouTube to try to find a clip of the show, which I remember vaguely as a young'un (it ran from 1961 to 1966), and was shocked to see how awful it was, though I also remembered correctly is it was a fantastic depiction of what young people called "square" in the 60s (it means "old school," but not in a good way).
Perhaps this will shed some light , for those of you under forty-five, to see where hippies came from, even beatniks. It was in reaction to "Sing Along with Mitch." Think Eisenhower era, conformist and conservative and bland. Sure there was some cool stuff that came down the pipe culturally, but the majority of Americans were in the Mitch-Miller camp. (Poll: who thinks minstrel shows minus blackface are racist anyway? I do.)
I had actually forgotten that Mitch's singers were all men. Creep-a-licious!