Korean football player Koo Ja-cheol speaks during his retirement press conference at the Korea Football Association House in Seoul, Jan. 14. Yonhap

Koo Ja-cheol, captain for Korea at the 2014 FIFA World Cup, announced his retirement from football Tuesday, with a second career with his former K League 1 club awaiting him.

Koo, who turns 36 next month, will work as a youth development adviser for Jeju SK FC, the only Korean club he played for during his 17-year career.

Two separate stints with Jeju bookended Koo's time on the pitch. He was selected in the third round by Jeju at the 2006 K League draft, and he would go on to play four seasons there before taking his talent to Germany.

Koo dressed for three clubs in the top-flight Bundesliga — VfL Wolfsburg, FC Augsburg and Mainz 05 — between 2011 and 2019. Koo then played for Al-Gharafa and Al-Khor in Qatar for three seasons, before rejoining Jeju ahead of the 2022 season.

Koo only played in 28 matches combined from 2022 to 2024, including only three matches in his final season, due to injuries.

"My body wouldn't hold up any longer, be it my knees or my ankles," Koo said during his press conference at the Korea Football Association House in Seoul. "In the past, whenever I was injured, I could at least get a sense of when I'd be able to recover and return. In the past couple of years, it was difficult to figure out that timeline. I knew then I could hang up the cleats and not have any regrets.

"It was always my dream to return to Jeju and retire here," Koo continued. "I am really grateful that I was able to realize that dream."

Koo also made his mark internationally. He was the top scorer at the 2011 Asian Football Confederation Asian Cup with five goals and helped Korea finish in third place.

He captained the under-23 Korean squad to the bronze medal at the 2012 London Olympics, the country's first and so far only Olympic medal in football. The midfielder played in every match and scored the second goal of Korea's 2-0 win over Japan in the bronze medal contest.

Asked how he'd like to be remembered as a player, Koo said, "If people remember me as someone who played on the first team to win an Olympic football medal for Korea, that would make me really happy."

Korean football player Koo Ja-cheol bows during his retirement press conference at the Korea Football Association House in Seoul, Jan. 14. Yonhap

Two years later, Koo was named captain of the senior national team for the 2014 World Cup. Korea only managed a draw and two losses in the group stage, with Koo scoring in a 4-2 loss to Algeria in the second match.

Koo retired from international play after the 2019 AFC Asian Cup in the United Arab Emirates, following Korea's exit from the quarterfinals. He logged 76 caps and scored 19 goals for the Taegeuk Warriors.

Looking back on his only World Cup appearance, Koo said he might have been too young and immature for captaincy in the summer of 2014, when he was 25 years old.

"I know I will be referred to as the youngest captain for Korea in World Cup history, but I am actually not proud of that," Koo said, trying to fight back tears. "When I look back on those days now, I realize I didn't have nearly enough experience to even think about the social responsibility that comes with captaincy. I was able to grow from that, but our results at the World Cup let so many people down. I should have been a more responsible captain."

In his post-playing career, Koo will stay with Jeju SK FC and work with their youth development program.

"I've been preparing for this moment for several years. I wanted to do something to help develop and change Korean football," Koo said. "I don't want to rush into anything. I will take my time and make sure I finish what I start. I know I don't have all the answers. Out of respect to people who've been working with the club, I will stay out of their way for the first year but help them whenever they need me."

Koo said he has had extensive discussions regarding his new career with two other giants in Korean football, Lee Chung-yong and Ki Sung-yueng. Koo said the three close friends had been talking about what they each want to do after their playing careers are over, and Koo will now be the first one to move into a new arena.

"All of us have agreed that the important thing is to take it slowly and not try to do too much from the beginning," Koo said. "We all want to do something positive for Korean football, and do it wisely and smartly. And I believe both Sung-yueng and Chung-yong will have so much to offer to Korean football later."

According to the club, Koo will help Jeju follow in the footsteps of top European clubs, and establish strong youth development and training programs.

Koo will also help set up opportunities for Jeju's youth players to train overseas and work with Jeju's scouts to check on foreign players.

Jeju also said Koo will play an important role in the club's marketing activities.

"I want to be able to identify good young players and develop them to help improve Jeju's squad," Koo said, "And I want to make sure they will continue to grow after they reach the K League and help them take their careers to places like the Premier League and the Bundesliga." (Yonhap)