There were a lot of great older characters on the classic TV shows we grew up with. Who was your favorite supporting senior gentleman?

Other - Jim Backus (Gilligan’s Island)

Mr. Wilson (Joseph Kearns) on Dennis the Menace
Rolly on Amen

I went with Howard McNear as Floyd, but Frawley as Fred and Bub would be very close. too.

Obviously I should've mentioned Peter Boyle (Frank Barone) on Everybody Loves Raymond.

Does Conrad Bain count? He certainly looks older, but on Diff'rent Strokes I always thought of him as a parent of teenagers/adolescents who just happens to have gray hair. And I don't know whether you want to differentiate between "supporting" and "main" characters ... Bain's definitely the lead (adult) character on DS.