He was the tribute of the 50th Hunger Games, and came out as their victor after tricking and killing Jared Halley.
In THE MARRISSA GAMES, he has become a druggy jerk, and befriended Atbod and P-Las, who later turned out to be Atlas and P-Body under disguise. During the course of the story, he switches back and forth in regards to alcoholism, and neglects training Prim, Peeta and Marrissa until their battle with Frank Fifteen.
After the battle, however, he allows them to practice their weapons. This allows them to collectively win the 74th Hunger Games and overthrow Critics United. Under the new rule, Haymish runs an AA place together with Whip Whittaker.