[2] At the age of 14, in 2009, he scored second-place honors in the Bridgestone Cup and Trophée de France, alongside registering a fourth-place finish in the French Karting F3 Championship.

He and co-driver Memo Rojas would go on to take the LMP2-class championship that season, finishing no lower than fourth and scoring podiums at Silverstone, the Red Bull Ring, Paul Ricard, and Spa, adding a victory at Monza.

[7] Following the European Le Mans Series season, Roussel took part in the final two races of the 2017 FIA World Endurance Championship, replacing Pierre Thiriet.

Roussel returned to professional motorsport in 2021, joining Saintéloc Racing in the GT World Challenge Europe Sprint Cup alongside co-driver Christopher Haase.

For 2022, Roussel stepped up to the GT World Challenge Europe Endurance Cup, competing in the Pro class for Emil Frey Racing alongside Giacomo Altoè and Arthur Rougier.