Trivia

In one of his appearances on Seinfeld Và Những Người Bạn (1989), he plays a homeless man that refuses to give Kramer's (Michael Richards) Tupperware back. In Napoleon Dynamite: Cuộc Sống Mới (2004), his character is a door-to-door salesman of Tupperware-like products.

On Mất Tích (2004) he played the father of Michael Emerson, who is actually 3 years older than him.

Son of noted writer/director/producer Tom Gries and actress Mary Munday. His paternal step-grandfather was jazz musician Muggsy Spanier (who was married to Jon's grandmother, Ruth).

Played the role of a wolf man in 2 films, in The Monster Squad (1987) as Desperate Man (wolf man in human form) and in Fright Night Part 2 (1988) as Louie.

He is the son of director Tom Gries.

Does not drink milk and eats very little red meat.

He is of German Jewish descent on his father's side.

Coincidentally has been in two movies with Sandy Martin. They were Uncle Rico and Grandma in Napoleon Dynamite, and 19 years earlier, they were both in Real Genius where she played an administrator, in a very small role, directing Mitch (Gabriel Jarret) to a freshman tea, and he played Lazlo Hollyfeld. The two movies share no other commonality - not in casting, directing, producing, writing, etc.

Brother of Cary Gries.