Lee Jae-sung (; born 10 August 1992) is a South Korean professional footballer who plays as an attacking midfielder or winger for Bundesliga club Mainz 05 and the South Korea national team.
Lee joined Jeonbuk Hyundai Motors in 2014 and made his debut in the 2014 AFC Champions League match against Yokohama F. Marinos on 26 February. Choi Kang-hee, the manager of Jeonbuk at the time, praised his ability which kept balance about attack and defense of team, and actively used him, the newcomer.
In 2016, he spent his best season by providing 17 assists during a year and winning the 2016 AFC Champions League.
In the 2017 K League 1, he won the Most Valuable Player award after having eight goals and ten assists during 28 appearances.
In July 2018, Lee joined 2. Bundesliga club Holstein Kiel on a three-year deal until 30 June 2021. The transfer fee paid to Jeonbuk was reported as â¬1.5 million. He played his first game against Hamburger SV on 4 August, and was named the player of the matchday by leaving a deep impression on kicker with two assists.
After the end of the 2019âÂÂ20 season, his goal against Karlsruher SC was selected as Kiel's Goal of the Season.
On 13 January 2021, he played full time and scored the fourth penalty in a 2020âÂÂ21 DFB-Pokal match, where Kiel won 6âÂÂ5 on penalties after drawing 2âÂÂ2 against Bayern Munich. Afterwards, Kiel reached the semi-finals of DFB-Pokal for the first time in history, but they were eliminated by Borussia Dortmund.
Kiel also finished third in the 2020âÂÂ21 2. Bundesliga, qualifying for the promotion play-off. In the two-legged play-off, Lee scored a goal and provided an assist, contributing to all two of Kiel's goals, but they lost 5âÂÂ2 on aggregate to Köln.
In July 2021, Lee joined Bundesliga club Mainz 05 on a three-year deal until 30 June 2024.
Lee was named the player of the 22nd matchday by kicker after dominating Borussia Mönchengladbach including a goal and an assist on 24 February 2023. In that month, he was nominated for the Bundesliga Player of the Month by leading Mainz to three Bundesliga victories as well as having three goals and two assists, but lost to Julian Brandt. He was also nominated for the Bundesliga Team of the Season because of his steady performance during the 2022âÂÂ23 season, but failed to be selected.
Lee seemed lethargic while Mainz earned only one win in the first half of the 2023âÂÂ24 season, but he played a key role in saving his team from relegation during the second half of the season.
Lee scored two goals in a 2âÂÂ1 win over Bayern Munich on 14 December 2024, leading Bayern to their first defeat in the 2024âÂÂ25 Bundesliga. During the 2024âÂÂ25 season, he had seven goals and six assists (ten assists according to the standard of kicker) in 33 league appearances, helping Mainz qualify for the 2025âÂÂ26 UEFA Conference League.
After coming on as a 60th minute substitute in a league phase match of the 2025âÂÂ26 Conference League on 6 November 2025, Lee had one assist and the winning goal, converting Fiorentina's 1âÂÂ0 lead into Mainz's 2âÂÂ1 win. The goal was his first goal at UEFA competitions excluding qualifiers.
In the 2017 EAFF Championship, Lee led South Korea's title, and was named the Most Valuable Player and the Best Duel Player.
Lee was named in South Korea's squad for the 2018 FIFA World Cup, and played all three games in the group stage. He also participated in the 2022 FIFA World Cup, helping South Korea advance to the knockout stage.
On 10 October 2025, he made his 100th international appearance in a friendly match against Brazil.
Lee possessed the ball for a short time, and showed great influence when moving without the ball. He preferred passing in a fast tempo to carrying, and had a high work rate to preoccupy suitable spots. His movement was also skilled in interceptions when defending.
Jeonbuk Hyundai Motors
South Korea U23
South Korea
Individual