Lee Chun-soo (; born 9 July 1981) is a South Korean former professional footballer who played as a winger and attacking midfielder. He was known for his pace, dribbling ability, and proficiency at free kicks.

Lee began his professional career with Ulsan Hyundai Horang-i in 2002, winning the K League Rookie of the Year award. In 2003, he became the first South Korean to join a La Liga club when he signed for Real Sociedad. After a loan spell at Numancia, he returned to Ulsan in 2005, helping the club win the league title and winning the league's MVP award. He subsequently played for Feyenoord and clubs in South Korea, Saudi Arabia, and Japan, finishing his career at Incheon United in 2015.

Lee scored 10 goals in 78 appearances for South Korea between 2000 and 2008. He appeared in all seven matches as the team reached the semifinals of the 2002 FIFA World Cup. At the 2006 FIFA World Cup, he scored a free kick against Togo in South Korea's first World Cup victory outside their own country. He also competed at the 2000 and 2004 Summer Olympics and helped South Korea finish third at the 2007 AFC Asian Cup.

Lee was known for his outspoken manner and confrontational behavior during his playing career, which was also marked by disciplinary suspensions and disputes with clubs. After retirement, he worked in football administration and became a television personality and football commentator. As of 2021, he also runs the YouTube channel Richunsu.

Early life Lee was born in Incheon and began playing football in the fourth grade at Bupyeong Elementary School. He then attended Bupyeongdong Middle School and Bupyeong High School. Lee's family experienced financial difficulties after his father's employer went bankrupt while Lee was in middle school, and he frequently struggled to pay his football team's boarding fees during high school.

Lee initially was not a starter for his high school because of his small stature but trained at night to improve his fitness. He and his school teammates Choi Tae-uk and Park Yong-ho were known as the "Bupyeong trio"; all three later represented South Korea at senior level.; ; Lee first attracted attention in 1998, when he helped Bupyeong win the autumn high-school football federation tournament, finishing as its top scorer with eight goals. He then helped the school win three titles in 1999, and professional clubs sought to recruit him later that year.

Lee entered Korea University in 2000, turning down professional offers on the understanding that he could pursue a move abroad. That March, he helped the university win the President's Cup. His performances in 2000 earned him the nickname "Millennium Express" (). Lee left university after his second year and joined Ulsan Hyundai Horang-i in February 2002.

Club career Ulsan Hyundai Horang-i Lee signed a five-year contract with Ulsan Hyundai Horang-i in February 2002, with the club agreeing to support a future move abroad. He scored on his professional debut against Suwon Samsung Bluewings on 10 July 2002.

Lee recorded seven goals and nine assists in 18 appearances during the 2002 K League season. He helped Ulsan win their final eight matches and finish as runners-up. He won the league's top assist provider award and was selected for the Best XI. He was also named Rookie of the Year, receiving 73 of 74 votes.

In May 2003, Lee was named the Asian Football Confederation's Young Player of the Year for 2002. He recorded eight goals and six assists in 18 league appearances for Ulsan in 2003 before joining Real Sociedad in July.

Real Sociedad In July 2003, Lee joined Real Sociedad for a transfer fee of US$3.5 million, signing a three-year contract with an option for a fourth year. He became the first South Korean to join a La Liga club.

Lee made his competitive debut against Espanyol on 30 August 2003. The match ended in a 1–1 draw, with Darko Kovačević scoring Sociedad's equaliser by finishing Lee's chip over the goalkeeper. Lee was credited with an assist. That September, he told Korean reporters that he hoped to move to Barcelona within two years and join Real Madrid two years later.

Lee made 21 competitive appearances during the 2003–04 season, including 13 in La Liga and six in the UEFA Champions League, without scoring. Reflecting on the move in 2018, Lee said that he had been unprepared to live abroad and had struggled to adapt to a different culture. He recalled difficulties connecting with manager Raynald Denoueix and credited teammate Javier de Pedro with helping him settle in.

Loan to Numancia In August 2004, Lee joined Numancia on a season-long loan. He initially impressed, with Spanish sports newspaper AS selecting him as its player of the match against both Getafe and Albacete in September.

By January 2005, Lee had lost his place in the side, and manager Máximo Hernández publicly expressed concern about his form and condition. He made 16 competitive appearances for Numancia without scoring.

Reflecting on Lee's spell in 2024, his former coach Francisco said that language difficulties forced him to explain tactics through diagrams and left Lee feeling isolated. Teammate Juanlu recalled that Lee impressed in training but struggled to reproduce those performances in matches, despite his teammates' efforts to help him settle.

In March 2005, Numancia and Real Sociedad agreed to terminate the loan early. Lee returned to South Korea to recover from a hamstring injury, and Sociedad agreed that he would rejoin Ulsan Hyundai Horang-i at the end of the season.

Return to Ulsan Lee returned to Ulsan for the second half of the 2005 K League season. On 27 November, he scored a hat-trick and provided an assist in a 5–1 away victory over Incheon United in the first leg of the championship final. Ulsan won 6–3 on aggregate to claim their first league title in nine years. In the second leg, Lee became the fastest player to reach both 20 goals and 20 assists in the K League, doing so in 50 appearances. He recorded seven goals and five assists across the regular season and play-offs and received the league's MVP award at the end of the season.

In 2006, Lee helped Ulsan win the Super Cup. In August, he scored six goals in three matches as Ulsan won the A3 Champions Cup, including a hat-trick in a 6–0 victory over Gamba Osaka. He finished as the tournament's top scorer and most valuable player. His season ended in October when he received a six-match suspension and a ₩4 million fine for verbally abusing match officials during a league game against Incheon.

In June 2007, Lee scored the only goal of Ulsan's League Cup semi-final against Suwon Samsung Bluewings with a free kick. He missed the final while on international duty as Ulsan defeated FC Seoul 2–1 to win the competition. In August, Ulsan agreed to sell Lee to Feyenoord for €2 million.

Feyenoord In August 2007, Lee agreed a four-year contract with Eredivisie club Feyenoord. He made his debut as a second-half substitute in a 1–0 league win over Excelsior on 20 October. In November, Feyenoord granted him two weeks' leave in South Korea while he was suffering from influenza and struggling to adjust to life in the Netherlands.

In January 2008, Lee assisted Jonathan de Guzmán's opening goal in a 4–0 win over SV Deurne in the round of 16 of the KNVB Cup. Feyenoord went on to win the competition, defeating Roda JC 2–0 in the final. Lee made 12 league appearances during the season without scoring. He underwent ankle surgery in May and spent his rehabilitation in South Korea.

In July 2008, Lee joined Suwon Samsung Bluewings on a season-long loan. Feyenoord's technical director, Peter Bosz, said that Lee had no immediate place in the club's intended system for the coming season and that the club hoped the loan would provide him with regular playing time.

Loan to Suwon Samsung Bluewings Lee was recovering from ankle surgery when he joined Suwon Samsung Bluewings in July 2008. He made his debut as a substitute in a 1–0 league win over Gyeongnam FC on 23 August. Four days later, on his home debut, he came off the bench to score the only goal in a League Cup group-stage victory over Incheon United.

Lee suffered a groin muscle tear in September, for which he was prescribed up to four weeks of rest and rehabilitation. He ultimately made four appearances for Suwon, scoring once. His spell was also marked by disagreements with the coaching staff. In December, he apologized to manager Cha Bum-kun for failing to repay his support with strong performances.

On 24 December 2008, the K League declared Lee ineligible to play at Suwon's request, after the club cited his absence from training and failure to follow the coaching staff's instructions. Suwon lifted the restriction in February 2009, allowing him to join Jeonnam Dragons on loan.

Loan to Jeonnam Dragons On 26 February 2009, Lee joined Jeonnam Dragons on a loan scheduled to run until January 2010. Jeonnam manager Park Hang-seo had persuaded Suwon manager Cha Bum-kun to allow the move.

Lee scored a late free kick on his debut against FC Seoul on 7 March, in a 6–1 defeat. During the match, after a goal was disallowed for offside, he made an obscene arm gesture and an apparent shooting gesture towards an assistant referee. On 10 March, the K League suspended him for six matches, fined him ₩6 million and ordered him to carry the fair-play flag before three home matches. In 2021, Lee said that the apparent shooting gesture had been an attempt to plead with the official that was misinterpreted because of the camera angle.

Returning from suspension on 26 April, Lee scored and provided an assist in a 4–1 away win over Suwon, Jeonnam's first league victory of the season. He scored four goals in seven league appearances during the loan.

Lee's loan ended amid a dispute over a proposed transfer to Saudi Arabian club Al-Nassr. Following a disagreement with the coaching staff, Lee left the team on 28 June. Jeonnam requested the League that he be made ineligible to play in the K League, citing missed training, failure to follow instructions, and his unauthorized departure. The league imposed the restriction on 1 July. The ban prevented him from playing in the K League without Jeonnam's consent but permitted an overseas transfer. Lee's transfer from Feyenoord to Al-Nassr was confirmed later that month.

Al-Nassr Lee joined Al-Nassr on a one-year contract in July 2009. In December, he scored twice in a 3–1 league victory over Al-Fateh. He sustained a rib injury later that month and made a series of substitute appearances after returning in January 2010.

On 17 March 2010, Lee returned to South Korea amid a dispute over unpaid wages. He said that Al-Nassr owed him three months' salary, a signing bonus, and other allowances. Al-Nassr said that Lee had left without permission and referred the matter to the Saudi Arabian Football Federation.

The Saudi Federation's refusal to issue an international transfer certificate delayed a move to Japan, but intervention by FIFA allowed Lee to join Omiya Ardija in August 2010. In April 2014, Al-Nassr reported that it had settled the outstanding payments, and Lee's complaint to FIFA was withdrawn.

Omiya Ardija After training with the club on trial, Lee joined Omiya Ardija in August 2010 on a contract for the remainder of the season. He made his debut on 15 August, playing the full match in a goalless draw with Júbilo Iwata. Lee's first goals for the club came on 5 September, when he scored twice and provided an assist in a 4–1 victory over Kamatamare Sanuki in the Emperor's Cup. In December, he extended his contract for another year.