Marty was married to Mrs. Chonks and ran the Bitch'n' Dog Food Factory in Trenton, Portland Island, Liberty City. He has grievances with many people, which he took care of by killing them and turning them into dog food.
Marty Chonks eventually employs Claude to transport various people to his factory, and then destroy any evidence in the car. Victims include his bank manager, two burglars and his wife, Mrs. Chonks. Marty then sends Claude to get Carl, who had been having an affair with Mrs. Chonks, who Marty believes he can overpower. Carl brings a shotgun and kills Marty, saying that he's there to take over the business. Claude has the opportunity to kill Carl after the mission, and see Marty's dead body before it disappears.
The missions that Marty gives are a spoof of the 1989 film "The Cook, the Thief, His Wife & Her Lover". The missions are entitled The Crook (the bank manager), The Thieves (two burglars), The Wife (Mrs. Chonks) and Her Lover (Carl), although the movie ends with the wife killing her husband, as opposed to Marty killing his wife.
- Marty's accountant - Murdered for stealing a share of Marty's earnings.
- Two thieves - Murdered so they would not be able to inform the police that he had employed them to break in to his house.
- Mrs. Chonks - Murdered due to her lavish spending and infidelity.
- GTA III
- Marty Chonks is the only pay phone mission boss in GTA III who physically appears in-game, unlike El Burro, King Courtney and D-Ice. King Courtney, however, appears in person in GTA Advance and El Burro has his own artwork.
- Marty, Mrs. Chonks and Carl do not have a proper skin in the game, since their designs are those of common pedestrians.
- The missions that Marty gives the player become unintentionally difficult after you've unlocked the second island as Marty's cars have no tolerance for gunfire as even a single shotgun blast from the Leone Mafia will destroy a car with no previous damage.
- Marty Chonks' missions are available after the mission Drive Misty For Me, although he does not appear on the radar, though you can hear the phone ringing while near Joey Leone's Garage.
- Marty's string of missions are a reference of the 1989 romantic crime drama The Cook, The Thief, His Wife & Her Lover, although the first mission is changed into The Crook.