He and two other gang members arrive at Pronghorn Ranch, where they are seen harassing Abe. He tells Abe to convince his boss to sell the land, threatening to start killing people on the ranch otherwise. He then fires his revolver near to Abe's feet to scare him, saying that he’ll be the first to be killed. John Marston intervenes, and the gang leader insults him. John calls his gang “vermin”, angering the gang leader. He then punches at John, who dodges, starting a fight. John defeats the gang leader and continues beating him up, until Abigail intervenes and tells John to stop. The gang leader threatens to return to the ranch and leaves with the two gang members.
A few days later, the Laramies attack the ranch in the middle of the night. They kill a ranch worker, set fire to the stables and steal the cattle. Geddes asks John, Abe, and Dickens to help him get back his cattle. The group heads to Hanging Dog Ranch, where the Laramies were holed up. John, Abe, and Tom attack the hideout and successfully recover the cattle. John finds the Laramie Leader in the ranch's barn, where the two get into a fist fight. The leader grabs a Sawed-off Shotgun to shoot at John, but John kicks the gun out of his hand and knocks him to the floor. The Laramie leader taunts John one final time before John kills him with his own shotgun.
The leader of the Laramie gang is shown to be very cruel, and has little regard for the lives of others as long as it lines his pockets. He also appears to be attracted to Abigail, as his last words involve wanting to sleep with her. However, considering his animosity towards John, it's possible he was merely taunting him.
It was widely speculated that the Laramie gang leader was voiced by Steven Ogg due to him sounding similar to Grand Theft Auto V's Trevor Philips, although he confirmed that he did not voice the character.
Tell your friend, Mr. Geddes, he's gonna sell this place...