Jens Castrop was born on 29 July 2003 in Düsseldorf, Germany, to a German father and Korean mother. He developed in German football through the academies of Fortuna Düsseldorf and Köln before moving into senior football with Nürnberg, where his intensity and tactical flexibility stood out.
At Nürnberg he became a reliable Bundesliga 2 midfielder, capable of playing centrally or as a wing-back. Borussia Mönchengladbach signed him for the 2025-26 season, giving him a Bundesliga platform and placing him in a stronger environment for his defensive duels, pressing and possession decisions.
As of May 2026 Castrop plays for Borussia Mönchengladbach. His club role has grown during the season, and his form in Germany has made him one of the most interesting additions to South Korea's World Cup pool because he brings Bundesliga tempo and a different development background.
Castrop switched international allegiance to South Korea in 2025 and made his senior debut that year, becoming a landmark figure as a foreign-born, mixed-heritage player in the Korean national team. He has been part of the 2026 World Cup build-up and has spoken publicly about representing Korea.
At around 1.78 m, Castrop is a right-footed midfielder or wing-back with aggression, stamina and tight-space competitiveness. His style is closer to a pressing Bundesliga eight than a traditional Korean playmaker, with comparisons to Park Ji-sung for work rate and to a younger Christoph Kramer for German midfield schooling.