Claim: Matthew Modine performed the character Dr. Martin Brenner.

Matthew Avery Modine -LRB- born March 22 , 1959 -RRB- is an American film actor who rose to prominence through his role as United States Marine Corps Private Joker in Stanley Kubrick 's `` Full Metal Jacket '' . His other well-known roles include Dr. Martin Brenner in Stranger Things , the title character in Alan Parker 's Birdy , high school wrestler Louden Swain in Vision Quest and the oversexed Sullivan Groff on Weeds .