In The Stranger Things Series :
In real life:
David Harbor 1, born April 10, 1975 in New York, is an American actor.

David Harbor takes lessons at Byram Hills High School in Armonk (New York State), along with actors like Sean Maher or Eyal Podell. He then graduated from Dartmouth College in Hanover (New Hampshire) in 1997.
Age : old.
Attribution - Sources - licenses