- "These clubs were custom made in Japan! The grips are seal skin! I have sensitive palms!"
- ―Mark Fostenburg
Fostenburg is a film star who regularly plays loner police officers in action films, and is also movie director. According to the Vinewood Star Tours guide, in 2007, a fifteen year old Mexican girl was found dead in Fostenburg's pizza oven. The case was settled out of the court and all the charges where dropped. The girl's family now lives near Mark's mansion in Vinewood Hills.
Events of GTA V
Fostenburg appears during the Strangers and Freaks side-mission Vinewood Souvenirs - Mark, in which protagonist Trevor Philips is tasked with retrieving Fostenburg's unique golf club for Nigel and Mrs. Thornhill. He will be found at Los Santos Golf Club and will be surrounded by three armed bodyguards. If Trevor gets too close or pulls out a gun, the guards will shoot at him and Mark will try to flee the golf club.
Although it's possible to get the golf club without killing Mark, one of the gold medal objectives of the mission requires the player to kill Mark with a headshot and another requires the player to kill him and all 3 of his bodyguards.
If the player doesn't kill Fostenburg, he will post a Bleet in the Bleeter website after the mission, complaining about the robbery.
He appears to be based on Bruce Willis, although his name is strikingly similar to Mark Zuckerberg's. Similarities to Willis include Fostenburg's starring role in the Die Already film series which in title and subject are reminiscent of Willis' Die Hard films. In terms of appearance, both men have shaved heads.
- He mentions that he has a property in Milan, while playing golf.
- He also says that he has a doppelganger playing golf in Omsk, probably to outwit paparazzi.
- According to Beverly Felton during his first mission, Fostenburg once had an extramarital affair with actress Miranda Cowan and it led to a divorce between Fostenburg and his then-wife.