2006–2011: Early achievements
Koon began playing poker in 2006 while still in college. He played initially online under the alias JAKoon1985 on PokerStars and NovaSky on Full Tilt Poker. He played low- to medium-stake online tournaments in the early years. In April 2009, he won a tournament in the Spring Championship of Online Poker earning over $300,000 prize money.
In 2011, Koon chopped a Full Tilt Poker "FTOPS" event that had 11,343 runners for $458,550. Koon's online earnings had exceeded $2.4 million by 2011.
Koon started participating in live poker games in 2008. His first foray into live poker failed, but he won his first live cash at the 2008 Deep Stack Extravaganza in Las Vegas. Koon played in his first WSOP in 2009 where he cashed twice. In 2010, Koon finished 4th in the World Poker Tour main event at the Bellagio for $225,000. He won $700,000 in three years from live poker.
In 2011, due to the fallout from the Black Friday case, Koon moved to Vancouver, Canada to continue playing online poker. Later in the year he moved to Cyprus. While in Vancouver, he roomed with Ben Tollerene who helped him play a more mathematical game. This year he also started to play and win medium to higher stakes games.
2012–2016: Live and online success
In 2012, Koon played in the high roller event at the Bahamas EPT event earning over $270,000. At the 2012 WSOP Koon finish 2nd in the $3,000 No Limit Hold'em/Pot Limit Omaha - Heads-Up event earning $128,660.
In 2013, Koon finished runner up to David Peters in the $10,000 Bellagio Cup earning $316,000.
In 2015, Koon turned $100 into $110,820 after 18 hours of play finishing third in a low buy in event at the SCOOP on PokerStars. He won $842,084 in total in 2015, which he considered "roughly break-even" due to the stakes involved.
Koon started a series of major successes in 2016. He won $514,080 in the $25,000 NLHE Bellagio High Roller 7 in Las Vegas. He won his first million dollar prize in the Seminole Hard Rock Poker Open, defeating Seth Davies in heads up. He won $2.89 million in 2016.
2017–present: Super high roller wins
In 2017, Koon won $1,650,300 in the PokerStars Championship $100,000 Super High Roller event in the Bahamas. Later in the year Koon won a large pot off Doug Polk in the hybrid cash game on Poker After Dark. He won $4.3 million in total in 2017.
Koon's most lucrative tournament win to date was in Triton Poker's 2018 Super High Roller Series Montenegro in Budva. In a short-deck ante-only tournament with a HK$1 million buy-in (US$127,000 at tournament time) and 103 entrants, he won HK$28,102,000 (US$3,579,914), defeating Xuan Tan in heads-up play.
In August 2019, Koon finished 2nd in the Event 3 of London Triton Poker Super High Roller Series (£50,000 No Limit Hold'em - 8 Handed) for £907,000.
On January 13, 2021, Koon made his debut on High Stakes Poker after filling the seat left empty by Jean-Robert Bellande in Episode 5 of Season 8. Koon bought in for $300,000 and the game was $400/$800 No-Limit Hold'em. In June, he finished third at the U.S. Poker Open, earning $336,000. During the 2021 WSOP, Koon won Event #11, the $25,000 Heads-Up No-Limit Hold’em Championship for his first WSOP bracelet.
In October 2022, Koon won Event #10: $50,000 No-Limit Hold'em of the 2022 Poker Masters. Koon topped a 37-entrant field to win $666,000. In December 2022, Koon faced off with Phil Hellmuth in Round 5 of PokerGO's High Stakes Duel 3. Koon defeated Hellmuth and won the $1,600,000 prize while advancing to Round 6. Koon finished third overall on the 2022 PokerGO Tour leaderboard with 2,833 PGT points. Koon was one of the 21-eligible players that were able to participate in the season-ending PGT Championship. Koon finished Day 1 as the overwhelming chip leader before winning the event after defeating Sean Winter heads-up for $500,000.
In January 2023, no challenger stepped up to take on Koon in Round 6 of High Stakes Duel 3, and he was declared the champion. On February 18, 2023, Koon won the 3rd annual World Series of Art Poker in Los Angeles, CA. The unique artist based tournament is put on by Stussy, Casinola, and Wood Kusaka Studio every year coinciding with LA's art fair week. Later that year, on May 22, Koon triumphed against Sam Greenwood, winning the $100,000 Triton Main Event in Cyprus and taking home $2,451,082. In December, he finished second in the $100,000 Ultra High Roller event at the WSOP in Bahamas which earned him $1,817,000.
In May 2025, Koon won $3,393,656, the second-largest prize of his career thus far, at Triton Poker's $150,000 no-limit hold'em event in Montenegro. He followed this with another win in the final event of the series, the $30K PLO Bounty Quattro event, which was his 12th win at Triton Poker. He had more than twice as many wins at Triton than the nearest competitors who each had five. In June 2025, he also won $1,968,927 and his second WSOP bracelet in the $50,000 High Roller event. This took his career winnings to $66 million, third in the all time money list.
In May 2026, Koon won €1,000,000 ($1,173,378) in the 100K European Poker Tour Monte Carlo Sit & Go tournament with a 'winner take all' format. As of June 2026, Koon's total live tournament earnings exceed $77 million. He stands 3rd in the world all-time money list in 2026.
