Maybe not a folkie, whatever that means, but a very great artist who had a huge repertoire of folk songs. He was as much a folk singer as anybody who ever did the folk festival circuit.

He was also, in my opinion, one of the best tenors ever recorded, but he isn't generally ranked with Carlo Bergonzi, Franco Corelli, Pavarotti, etc because he didn't make a career singing opera. He did start out on the opera stage, but decided that was not what he wanted to do with his life. Listen to his classical recordings. He had it all.