He was a Jesuit priest who left the order in 1974 to pursue other interests, though nobody seems to know what those were. (I read a few obits and mini-bios and nobody mentioned the period 1975-1981).
Presumably at least part of that time he was writing speeches for Nixon and Ford.
Before Thanksgiving, rather than end the show with his signature "bye, bye!", he said "Gobble, gobble!"