According to okdiario.com, the transfer fee is put at around €40 million, making Kang In Lee the club's third summer arrival after left-back Alejandro Grimaldo, signed from Bayer Leverkusen, and midfielder Morten Hjulmand, who joined from Sporting CP.
The 25-year-old, born in Incheon, returns to LaLiga after two spells in Spanish football. He joined Valencia's academy at the age of ten and made his first-team debut in a Copa del Rey tie on 30 October 2018, a competition Valencia went on to win that season. After 62 appearances for the Che, he moved to Mallorca in August 2021, where he made 73 appearances across two seasons under Luis García Plaza and Javier Aguirre before completing a switch to PSG in the summer of 2023.
At the Parc des Princes, Kang In Lee made 124 appearances, scoring 16 goals and providing 16 assists, and won two Champions League titles alongside three Ligue 1 titles, two French Cups and two French Super Cups. His role became more peripheral last season, when he featured 39 times but managed only four goals and five assists as PSG's attacking options deepened.
Internationally, Kang In Lee has 50 caps for South Korea and recently featured at this year's World Cup. He was named best player of the 2019 Under-20 World Cup, where South Korea finished runners-up, and won gold with the country's under-23 side at the 2023 Asian Games, beating Japan in the final.
Atletico Madrid described their new signing as a technically gifted left-footed player capable of operating as an attacking midfielder or from either flank, highlighting his passing range and ball-striking. He will wear the number 7 shirt, previously worn by club record scorer Antoine Griezmann, who left the Metropolitano this summer, and is set to join up with Diego Simeone's squad once his post-World Cup break ends.
The deal is understood to have been driven by sporting director Mateu Alemany, who knew him from his own time working at Valencia.
Atlético had shown interest before his 2023 move to Paris, when PSG moved ahead with an offer in the region of €15 million; the fee agreed this summer reflects his rise in value over three seasons collecting honours in France.