Youth Bornauw began his club career - unusually for a European player - in the youth ranks of
Moroccan First Division club
Wydad Casablanca when his father was working there.
Anderlecht Bornauw made his professional debut for
Anderlecht in a 4–1
Belgian Pro League win over
Kortrijk on 28 July 2018, at the age of 19. He played the full game. Bornauw would go on to become a key defender for Anderlecht, despite his young age. In total, he played in 24 league games and he scored one goal as a defender for Anderlecht in his debut season.
1. FC Köln On 6 August 2019, Bornauw joined
1. FC Köln on a five-year deal. He scored his first
Bundesliga goal on 20 October 2019 against
SC Paderborn. In his first season at 1. FC Köln, Bornauw established himself as a regular starter and became a key player for the club.
VfL Wolfsburg On 16 July 2021, Köln announced that the club had transferred Bornauw to
VfL Wolfsburg, where he signed a contract until 2026. He scored his first goal for Wolfsburg on 26 February 2022 in a 2–2 draw against
Borussia Mönchengladbach.
Leeds United On 1 July 2025, Bornauw signed for
Premier League club
Leeds United on a four-year deal, for a fee of £5,100,000. He made his Premier League debut on 3 December 2025, in the match against Chelsea, coming on as a late substitute for
Gabriel Gudmundsson. ==International career==