Did he ever act in anything after Christmas story?
Yes. He produces and acts. He was an executive producer on Iron Man and played a character in it and Spider Man: Far From Home:
"William Ginter Riva: Mr. Stane. Sir, we've explored what you've asked us and it seems as though there's a little hiccup. Actually, um...
Obadiah Stane: A hiccup?
William Ginter Riva: Yes, to power the suit... sir, the technology doesn't actually exist. So it...
Obadiah Stane: Wait, wait, the technology?
[puts an arm around him]
Obadiah Stane: William...
[points at the giant arc reactor]
Obadiah Stane: Here is the technology. I've asked you to simply make it smaller.
William Ginter Riva: All right, sir, that's what we're trying to do, but... honestly, it's impossible.
Obadiah Stane: [shouting]
Tony Stark was able to build this in a cave! With a box of scraps!
William Ginter Riva: Well, I'm sorry. I'm not Tony Stark."
https://www.imdb.com/title/tt0371746/quotes/?tab=qt&ref_=tt_trv_qu