Lee joined Mallorca in 2021, where he established himself as one of Europe's top dribblers, before leaving Spain for French club Paris Saint-Germain in 2023.

[4] Lee made his La Liga debut on 12 January 2019, substituting in for Denis Cheryshev in the 86th minute in a 1–1 draw with Real Valladolid during 2018–19 season.

[8][note 2] His record as the youngest non-Spanish goalscorer for Valencia was broken the following season by American teammate Yunus Musah.

[11] Despite rejecting several renewal offers from the club throughout the year,[12] he featured regularly under Javi Gracia as the Che ended the campaign on a mid-table position.

[13] On 30 August 2021, fellow La Liga club Mallorca confirmed the free transfer of Lee, signing on a four-year contract.

[21] On 3 January 2024, he was named man of the match, after he scored the opening goal in the 2023 Trophée des Champions final against Toulouse in a 2–0 victory, winning his first title with the club.

[25] Lee was called up for friendlies in September 2022 just before the 2022 FIFA World Cup by showing his evolution on both side of the ball in La Liga.

[34] After South Korea was eliminated in the semi-finals by Jordan,[35] however, it was reported that he had been in conflict with veteran players in the national team including captain Son Heung-min before the defeat.

[36] In 2007, the six-year-old Lee was featured in the third season of the KBS N Sports reality football show Fly Shoot Dori.

His father Lee Woon-seong was a taekwondo instructor in Incheon and a big football fan (especially of the late Diego Maradona).