Jeff is married to a woman named Shirley, has one son with her and is extremely paranoid that she is cheating on him. Jeff reveals in the final mission that his mom left his dad, which probably traumatized him into his current state. Despite having obvious mental problems and shabby clothes, he is an extremely wealthy businessman with a black credit card. Shirley became distressed by his paranoid behavior, such as sending her underwear to a laboratory and demanding she get a tracking device in her head. She then turned to another one of Jeff's wealthy friends for emotional support, and although he was secretly interested in having an affair with her, Shirley was only going to him for platonic friendship and was very naive to his obvious attraction cues.
Jeff discovers this and stalks them to his friend's apartment near Middle Park East, when he randomly encounters Niko Bellic. He pays Niko to take reconnaissance photos of his wife and friend (driving in the friend's Feltzer to the Superstar Café). Niko successfully sends him a cell phone picture and, seeing they were platonic friends, consoled Jeff that it wasn't necessarily proof of her cheating on him.
Ten game days later, Jeff calls Niko to request his services and meet him in an underground parking complex. (Receiving this call launches the mission, regardless what Niko is doing at the time). Despite Niko's advice, Jeff had violently stabbed his wife 50 times with a kitchen knife and hid her body in a Blista Compact, now asking Niko to dump the car in the Humboldt River. Niko has to drive to the dump site without police spotting the dead body in the back. (Note: 10 days do not always pass between completion of the first mission and receiving the phone call.)
Later in the game, Niko encounters Jeff again near a Little Italy restaurant. He has remarried in a remarkably short amount of time, and believes his new wife is cheating on him as well. He stalked her to the restaurant, where she was having a drink with her ex, and when Niko encounters him, Jeff requests that Niko kill her as well, which he refuses to do. After lamenting that he needs a friend, he runs out into the street and is run over by a Turismo. The driver, a stereotypical posh English man, gets out and calls the cops police to get help, before jumping into his car and racing away (unless Niko has stolen the car).
The last encounter with Jeff requires minimal interaction by Niko or the player - simply a cutscene to be viewed. There are two possible rewards: Jeff will drop several hundred dollars when he is killed, and if Niko is fast enough, it's possible to steal the Turismo. As noted below, while it is possible to change elements of the final encounter, it is not possible to prevent Jeff from being killed in some way. The "mission" ends a few moments after the hit-and-run driver pulls away, or Niko carjacks the Turismo.
- Jeff suffers from Angina, a severe heart condition, possibly due to his incredibly short fuse and violent temper leaving him frequently over-stressed and anxious.
- Jeff's "Black card" is a parody of the American Express Centurian and Visa Black Card, both black-colored credit cards given to multimillionaires.
- The only way to save him from his death is by parking a truck, van, fire truck, etc. on the left side of where he is sitting but on the street. This is a glitch because right where he was supposed to get hit, he will stand still. The only way to complete the mission now is by shooting him in the head. It is obvious you are not meant to sympathize with him.
- Jeff meets the same end as the GTA CW random character, Marcy.
- Jeff's mission's do not count towards 100% completion because it is possible for Niko to kill Jeff's wife when he goes to take a photo of her. This does not fail the mission and Niko will even phone Jeff to inform him. Killing his wife here makes it impossible for Jeff to kill her himself, so his later missions are disabled.
- It is possible to steal the car which Jeff gets hit by before the driver gets back in his car after making the phone call. It will not hinder the completion of the random character mission.
- If you kill the driver who ran Jeff over, a Mission Complete sound will play, and the wanted level you may get a second later will disappear. But if you aim a gun at him he'll try to get in his Turismo and try to escape.
- Sometimes when the Turismo drives away it will be blocked by traffic, offering a second chance for Niko to run after it and steal it.