His eldest brother, Eden, previously played for Lille in France, Chelsea in England and Real Madrid in Spain.

Thorgan moved to Dortmund in May 2019 (summer transfer window) and had previously progressed through the youth ranks of Lille's biggest rivals Lens.

[5] Hazard began his professional career at White Star Bruxelles, joining the club in 2013 from the Lille academy where he spent two years.

[18] Hazard made his professional debut for Zulte Waregem on 7 August 2014, replacing Ibrahima Conté after 69 minutes against Belarusian side Shakhtyor Soligorsk in the third qualifying round of the UEFA Europa League.

[23] On 29 August 2017, Hazard joined Premier League side Chelsea, and was put in the club's development squad.

[29] He made his competitive debut for the club on 13 February, coming on as a substitute for Thomas Ephestion in the 79th minute of a 1–0 Belgian First Division B win over Deinze.

[32] Hazard helped RWDM achieve promotion to the 2023–24 Belgian Pro League, however, he suffered an ACL tear in the summer of 2023 and was not able to appear for the club in the first half of the season.