Lee "Wolf" Jae-wan began his competitive career on December 21st, 2012 when he joined NaJin Shield as their new support. During this time, he went by the name "a Wolf". He played in his first major tournament at GIGABYTE StarsWar League Season 2 where his team failed to make it out of groups. Wolf came back to Korea to participate in his first OGN, OLYMPUS Champions Spring 2013. The team successfully made it past the group stage but got crushed 3-0 in the quarterfinals by the newly formed SK Telecom T1 2. Wolf left the team shortly after to join Chunnam Techno University. The team qualified for HOT6iX Champions Summer 2013 where they were swept in the quarterfinals again, this time by MVP Ozone. Wolf left CTU in October 2013 to join the newly reformed roster of SK Telecom T1 1. A few months later, the were renamed SK Telecom T1 S.
S participated in PANDORA.TV Champions Winter 2013-2014 where they failed to make it out of groups. Later on at HOT6iX Champions Spring 2014, the team lost in the group stages again. They had a breakthrough at HOT6iX Champions Summer 2014 where they made it to the semifinals but lost 3-2 to the KT Rolster Arrows and then 3-0 to Samsung Ozone.
With the changes to the OGN rules, S and their sister team SK Telecom T1 K were forced to merge to form SK Telecom T1. With PoohManDu's departure from the team, Wolf was made the starting support. The team participated in SBENU Champions Spring 2015 where they won the championship after beating the GE Tigers in the finals 3-0. SK Telecom's victory qualified them for the 2015 Mid-Season Invitational where they made it to finals but lost 3-2 to EDward Gaming. SKT placed first in the regular season of SBENU Champions Summer 2015 after only dropping one set the whole season. They beat KT Rolster 3-0 in the finals of the playoffs to qualify for the 2015 Season World Championship as the top seed from Korea. SKT was placed in a group at worlds alongside EDG, Bangkok Titans, and H2k Gaming. They went undefeated all the way to the finals, beating AHQ e-Sports Club and Origen in the playoffs along the way. They met the KOO Tigers in the finals and beat them 3-1 to give the organization its second World Championship.
SKT played in the 2015 LoL KeSPA Cup where they lost 2-0 in the semifinals to Ever. This series was widely considered to be one of the greatest upsets in League history but also continued a streak of World Champions being eliminated early on in their first tournaments after Worlds. In March, SK Telecom attended IEM Katowice despite being only the sixth-place LCK team at the time. They brought substitute jungler Blank in place of bengi and swept through the tournament, winning the title after only seven games. After their international success, they returned to Korea and placed third in the regular season, earning themselves a spot in the playoffs. SKT won the playoffs, winning their third championship in a row and giving them a seed to the 2016 Mid-Season Invitational.
Their first place finish in the spring season earned them a spot in the 2016 Mid-Season Invitational. Notably, SK Telecom T1 were the only team to return to 2016 MSI from 2015 MSI. As the reigning domestic champions of Korea, SK Telecom T1 came into the tournament as massive favorites to win. However, their group stage performances were very lackluster as they dropped games to China's Royal Never Give Up, NA's Counter Logic Gaming, and two games to the LMS Flash Wolves. They ended their group stage with a 6-4 record, seeding them into the bracket stage at fourth place. Matched up against Royal Never Give Up in the semifinals, SK Telecom started to regain their form, beating them 3-1. They then proceeded to beat Counter Logic Gaming 3-0 to win the event and give them the trophy that barely escaped them last year.
During the 2016 LCK Summer Split, SK Telecom started the season strong with a 5-0 score in series and 10-0 game score. However, they started dropping sets to lower ranked teams, notably the Afreeca Freecs, who they failed to win even a single game against the entire season. With a 13-5 scoreline in series, SKT placed second in the round robin, beating KT Rolster via game score tiebreaker. However, during the 2016 LCK Summer Playoffs, they met KT Rolster in the semifinals, where they were reverse swept 3-2 after going up 2-0 in the first two games. This gave them third place for the summer split. Combined with their first place spring finish, as well as the victory of the ROX Tigers over KT Rolster, SKT qualified to the 2016 Season World Championship on points as Korea's second seed.
At the 2016 Season World Championship, SK Telecom T1 were placed into Group B, along with LMS's Flash Wolves, NA's Cloud 9, and China's I May.