Postmaster General role in Seinfeld, which parodied his role in Absence of Malice. The Seinfeld role was played for laughs but there was a little bit of a dark edge to it, in a funny way.

https://www.youtube.com/watch?v=On3cQ0sPvSY (appearance about 1:17 in)

He was perfectly cast, and perfectly played, his role as a nuclear power plant technician in The China Syndrome.