Impact began his career as a support player for Xenics Storm in 2012, and the team managed to place third in spring.

[3] The team qualified for the 2013 World Championship as Korea's third seed,[4] and subsequently tore through the tournament, dropping only 3 matches in the entire event, capped with a 3–0 sweep of China's Royal Club.

[5][6][7][8] Following their World Championship victory, Impact and SK Telecom T1 K, won the winter split in the LCK, as well as All-Start Paris, before struggling in spring and summer, failing to place top 4 in either split, and missing out on the 2014 World Championship, where Impact was unable to defend his title internationally.

[26] Cloud9 qualified for the Regional Gauntlet at the end of the season, and defeated both Team Envy and Immortals to earn a spot at the 2016 World Championship.

[41] In summer, Cloud9 finished in fourth place in the regular season, but in the quarterfinals of the playoffs, Cloud9 were defeated by Dignitas in what was described as a "massive upset", and knocked out early.

[54] The win earned Team Liquid a spot at the 2018 Mid–Season Invitational,[55] where they went 4–6, losing a tiebreaker to Fnatic and placing fifth in the group stage, failing to advance.

[59] Due to their victories, Team Liquid qualified for the 2018 League of Legends World Championship as North America's first seed.

Impact left Team Liquid and joined Evil Geniuses in late 2020, ahead of the Spring 2021 split.

Evil Geniuses would go on to win the split, with Impact breaking his previous record of fastest LCS finals series, beating 100 Thieves in only an hour and 18 minutes.

FlyQuest managed a 14-4 record in the Spring split, yet fell short in playoffs to Golden Guardians, missing out on MSI 2023.

FlyQuest would go on to shock with a ninth place finish in the Summer split, and the team would announce Impact's departure on November 22.

[87] In returning to playing top lane for the team, he slotted into a roster including North American prospects Yeon and APA, as well as fellow Korean veterans CoreJJ and Umti.

Impact and his team went on to win the 2024 LCS Spring Split,[88] and earned a spot as the year's Mid-Season Invitational.