The basic reason why Stu changed from gin rummy to poker was that he was a bit too good at it. So good was he, that no player could stand up to him. Even the apparently professionals who were supposed to be the greatest at gin rummy were beat when they played with Stu. One of these gin masters was Harry Stein, nicknamed, "Yonkie". Harry was handed such a belittling blow at the hands of Stu Ungar that he evidently quit participating in it as a pro and never resurfaced at a gin rummy tournament.
Certainly, with a reputation like that it was not long before everyone became shy of playing against Stu Ungar. He could not find any matches and in his agony he started doing something no one had attempted before. Stu began offering beginning handicaps to potential competitors in the hope that they might compete opposed to him if they thought they had an edge. He at will played from a negative arrangement and one account has it that he even played against a constant bad egg. Mid match, he get warnings that the bad egg was at it yet again but Stu Ungar assured that he deduced of the fraudulent activity and he would still come away with a win, which of course, he did.
The same trend followed Stu Ungar to vegas. He won so frequently that the poker rooms began requesting that he not to bet in their respective premises anymore. The reasoning behind it was that other poker room clients refused to sit at the poker table if Stu was playing.
Stu Ungar is recollected more for his achievements in holdem poker but he himself always insisted that he was far more skilled at gin rummy.
He defeated Doyle Brunson in the World Series of Poker in 1980 and became the youngest world camp. Due to his looks that made him appear far younger than he was, he got the nickname, "The Kid".