Gumayusi

Early career (2018)

On December 18, 2018, Lee played in KeSPA Cup 2018 under the amateur team, KeG Seoul. His team defeated pro LCK team Hanwha Life Esports with a match score of 2–1.^[1][2]

T1 (2018–2025)

In December 2018, it was announced that Lee joined SK Telecom T1 under the name "Catan".^[3] During his time as trainee, he and four other trainees from T1, Canna, Ellim, Mask, and Kuri, competed in the 2019 LoL Amateur Tournament. The team was called 'T1 Rookies', and they won the tournament.^[4][5] On November 26, 2019, T1 announced that Lee was called up to the main roster.^[6]

Lee made his debut in the LCK at the 2020 Regional Finals.^[7] His debut match was against Afreeca Freecs, which he won with a match score of 3–1.^[8] On November 24, 2020, Lee re-signed with T1.^[9]

On January 13, 2021, Lee played his first game of the season in LCK Spring 2021. He served as the main player of the roster for the first time in his career. The game was against Hanwha Life Esports.^[10] Lee got his first pentakill in his career in the match against DWG KIA. He achieved the milestone with Aphelios.^[11] Lee was included in the roster for the 2021 League of Legends World Championship,^[12] in which he and his teammates ended the journey in the semifinals.^[13] On December 3, 2021, Lee re-signed with T1.^[14]

In the 2022 LCK season, Lee broke the record of the player with the most kills in a season, setting the record to 219 kills.^[15] He was also a member of the team that went undefeated in the regular season with a 18-0 record, becoming the first team to achieve this record in the LCK.^[16] Lee won his first LCK title with his teammates in the 2022 LCK Spring finals.^[17]

In 2023, Lee and T1 reached LCK Spring finals, where they lost to Gen.G. With finishing second place but qualified for the Mid-Season Invitational as the second seed, where they got defeated 3–2 by JD Gaming and 3–1 by Bilibili Gaming to exit the Mid-Season Invitational at the loser-bracket final. T1 finishing second in LCK Summer Finals in another rematch against GenG, with the most championship points in the LCK, the team qualified for the 2023 World Championship, marking Lee's third Worlds appearance. At Worlds, Lee and T1 won their fourth Worlds title on November 19, 2023. After going 3-1 in the Swiss Stage, Lee and T1 entered the Knockout Stage, where they first defeated the LPL second seed LNG Esports 3-0 in the quarterfinals. After defeating tournament favorites JD Gaming 3-1 in the semifinals, Lee and T1 defeated Weibo Gaming in the finals 3-0, marking Lee's first World Championship and T1's fourth. On November 23, 2023, Lee re-signed with T1.

At the 2024 League of Legends World Championship, Lee and T1 won their fifth Worlds title on November 2, 2024.^[18]

During the new tournament LCK Cup in 2025, Gumayusi was benched and replaced by the T1 Academy ADC Sin "Smash" Geumjae after 5 games.^[19]. T1 did not qualify for the tournament First Stand and he stayed benched until the regular Spring round. Gumayusi was not fully active, he and Smash were deployed alternately until the 14th of April. After pressure of fans and T1's CEO Joe Marsh's intervention, the coach team let Gumayusi be the main ADC again with no official announcement.^[20] T1 finished the split with 11 wins and 7 losses, placing them third in the rankings after Gen.G and Hanwha Life Esports. Gumayusi and T1 qualified for MSI 2025 after they beat Hanwha Life Esports with a dominant 3-0 win, earning the second seed, during Road to MSI 2025.^[21]T1 advanced to semifinals at MSI 2025, beating CFO and BLG. They met Gen.G at semifinals and lost 2-3 and dropped to the lower brackets, meeting AL. With a 3-2 win, Gumayusi and T1 enter the finals to meet Gen.G for a second time^[22]. Ultimately, the team lost 2-3 again, ending up as runner-ups. 2025 LCK second round introduced a new system, where all teams are put in two groups depending on their standing in the previous round. Due to T1 ending the Spring round in third place, they are put in the "Legends" group and kept their placement until the end of the round. With their standings, Gumayusi and T1 were automatically qualified for the playoffs for 2025 World Championship. With a loss to HLE, T1 dropped to the lower bracket's quarterfinals and lost to Gen.G. Because an LCK team won MSI 2025, four LCK teams can participate at Worlds 2025. After the loss to Gen.G, T1 qualified for Worlds 2025 as the forth seed.

At the 2025 World Championship, Lee and T1 won their sixth Worlds title on November 9, 2025 after defeating KT Rolster with a close 3-2 win. He was named tournament MVP after the finals by Hall of Legends inductee Uzi due to his strong plays with Miss Fortune, Kalista and Varus. Gumayusi will receive two skins, one for winning with T1 and a prestige skin for receiving the MVP award. His choices are Miss Fortune and Yunara^[23]. He becomes the player with the second-most skins after Faker.

On November 17, 2025, T1 announced that Gumayusi had left the team.^[24]

Hanwha Life Esports (2026–present)

On November 23, 2025, HLE announced that Gumayusi joined the team for the LCK 2026 season.^[25]