One of those character actors you never forget!
This guy was in literally hundreds of TV shows/movies from the 1970s to the 1990s. If a casting director needed a wise-talking New Yorker with an ever-present cigar, they called Brock.
I was first exposed to him during his run as Howie Hoffstedder on Days of our Lives between 1983-86. I guarantee everyone who watched the show during those years remembers him.
He even appeared in the inner-sleeve artwork of the 1987 Rush album, Hold Your Fire. I don't know how or why art director Hugh Syme chose him, but it's most definitely him!