Not sure as in total blank. Rance Howard (born Harold Engle Beckenholdt, who knew!)? Dennis Weaver? The guy that ‘voiced’ Ben?
And what sitcom is that or any of those actors? Not the faintest clue.
Ivan Tors, producer of Ben and its pilot film, Gentle Giant? The guy in the bear suit the second unit used for (long shot) B-roll setups?
I. Do. Not. Know, 
My 'secret'
I have not scene a single seen of Gentle Ben in any form, thus my use as a reference here is (to be generous) ‘cavalier.’
Consider it digital exhaust.
That I’m inflicting. On you.
Sorry. 