Bingo on all counts. Good on ya mate.
I looked it up after I posted to see if I got it right. He’s still around at 99 years old!
I knew it was William Daniels as answered above. No cheating….honest. I never watched the show but saw enough clips to recognize who it was. I first became aware of him in the Parallax View a conspiracy paranoia thriller that was quite memorable with Warren Beatty as the lead.