He won the 2015 Mid-Season Invitational with Edward Gaming and the 2022 League of Legends World Championship with DRX.

[2] Deft won his first domestic title in the 2014 Champions Spring Split, after Samsung defeated Najin Shield in the finals.

At around 35 minutes into game five, LGD had control around the Baron and looked to secure the Nashor to overcome a major gold deficit.

[5] Deft won his first international title at MSI, after Edward Gaming defeated SK Telecom T1 in the finals.

Deft and EDward Gaming qualified for 2016 World Championship, where they lost 1–3 in quarter-finals against ROX Tigers.

In Regional Finals, KT lost to eventual World Champions, Samsung Galaxy with a score of 0–3.

However, high placing in Spring Split allowed Kingzone DragonX to get a second chance at qualifying for World Championship, but the team ultimately fell in Regional Finals to DAMWON Gaming in a close, 2–3 effort.

The team was completed with rookies such as Pyosik and Keria from DragonX academy, and the Griffin duo Doran and Chovy.

At Mid Season Cup, DRX placed tied for 2nd in the group with a 2–1 record, but lost both tie-breaker games.

[21] Second place allowed Deft and his team to qualify for the World Championship, this time as the lowest LCK seed having to start the competition from The Play-In Tournament.

HLE placed 2nd in Play-Ins and managed to make it to the quarter-finals, where they eventually met T1 again, in a losing effort 0–3.

[29] On September 4, 2022, Deft and his team successfully secured the last LCK spot to the World Championship after defeating Liiv Sandbox with a match score of 3–2.

Deft was the oldest professional player to win the League of Legends World Championship before Faker broke his record on November 19, 2023.

"The important thing is an unbreakable heart," which was left in an interview with a media outlet by Deft, who defeated T1 at the time and lifted the trophy for the first time in his career, emerged as a buzzword, citing the Korean national soccer team that participated in the Qatar World Cup.

Deft returned to KT Rolster in 2024, citing a desire to play with old DRX teammates BeryL and Pyosik.

[36] Prior to going professional in 2011, Deft played League of Legends on the North American server;[37] his favourite champion is Jinx.

[39] In 2018, he was selected as one of the torch relay runners for the 2018 PyeongChang Winter Olympics, alongside his fellow kt Rolster teammates.