The primary reason why Mr. Ungar changed from gin to poker was that he was a bit too good at it. So good in fact, that no one possibly could stand up to him. Even the commonly called professionals who were meant to be the best at gin rummy were beat when they played with Mr. Ungar. One of these gin masters was Harry Stein, called, "Yonkie". Mr. Stein suffered such a crushing beating at the hands of Stu Ungar that he allegedly stopped participating in it professionally and never showed up at a gin tournament.
Of course, with a honor like that it wasn’t long before gamblers became weary of betting against Stu Ungar. He could not find any games and in his desperation he started doing something no one had performed prior. He began offering beginning handicaps to potential adversaries in the high hopes that they might play opposed to him if they thought they had an edge. He deliberately played from a bad arrangement and one account has it that he even competed with a regular bad egg. During the game, he get warnings that the cheater was at it yet again but stu stated that he knew of the fraudulent activity and he would still come away with a win, which he did, of course.
The same problem followed Stu Ungar into Las Vegas. He won so much that the poker rooms started requesting that he not to wager in their poker rooms anymore. The reasoning behind it was that other poker room customers would not sit at the poker table if Stu was playing.
Stu Ungar is remembered better for his achievements in texas hold’em poker but he himself always insisted that he was a whole lot more skilled at gin rummy.
He beat Doyle Brunson in the WSOP in 1980 to become the youngest world champion. Due to his looks that made him appear far younger than he was, he was nicknamed, "The Kid".