Lee Jae-sung is going to the FIFA World Cup 2026 with South Korea in the best form of his Mainz career, and that matters because his club season was built on more than reputation. The 33-year-old appeared in every Bundesliga game he was available for last term, scored six goals and set up four more, then finished with 1,943 intensive runs, a workload bettered at Mainz only by Paul Nebel and Kaishu Sano.
That is why the keyword is being searched now: Lee is not simply a veteran name in Myung-bo Hong’s squad, but a player who arrives with evidence that he can still drive a team forward. Hong has said Lee can fill any role and even wants to try him alongside Hwang In-beom in central midfield, a hint that South Korea may lean on his range rather than treat him as a narrow attacking option. He is also the second-oldest outfield player in the squad behind Heung-min Son, which only raises the value of what he brings on and off the ball.
His club season under Urs Fischer gives that trust a concrete base. Fischer took over Mainz last December and saw Lee score a header in his first game in charge, a 2-2 draw at Bayern Munich, before the midfielder struck a last-minute winner against Fiorentina in November in a 2-1 Conference League league-phase victory. Mainz ended the campaign in 10th place and reached the last eight of the UEFA Conference League, the first European quarter-final in the club’s history, with Lee central to both the league and continental push.
There is still a question inside all that productivity. Fischer has said Lee sometimes needs protecting from himself even while insisting he can play three times a week with no issues whatsoever, and that is the kind of balancing act South Korea will have to manage at a World Cup. Lee has been doing this for a long time — he made his international debut on 27 March 2015, now has 105 caps and 15 goals, and five of those goals came in World Cup qualifying — but the job in 2026 will be less about his past and more about how Hong uses him in the middle of the pitch.
He already knows the stage. Lee played every minute of South Korea’s group campaign at the 2018 World Cup and helped them reach the round of 16 four years later, so this tournament will not be new terrain. What is new is the shape of the trust around him: Mainz have proof he can sustain a heavy load, Hong wants his versatility, and South Korea may need both if Lee is to turn another solid club season into something bigger next summer.
