Sung started playing poker with Danny Wong, and plays online under the name "MuGGyLiCiOuS." He started playing major live tournaments once he turned 21 (approximately), and has had solid results in that time.

During his fourth World Poker Tour cash, Sung made the televised final table. He had come close twice before, finishing ninth and 12th. His strongest tournament series was the 2006 Bellagio Five-Diamond Poker Classic — he finished third in a $5,000 preliminary event, and then ninth in the $15,000 main event. He also added two WSOP final tables to his résumé this summer, with a third place in the $1,500 seven-card stud event and ninth in the $10,000 pot-limit Omaha event, proving that he excels in games other than hold'em. Then, at the 2008 Bay 101 Shooting Star event, Sung made another WPT televised final table. He went heads up for the title, but came in runner-up. He snagged $585,000 for his efforts.