Giusti made his car racing debut in 2021, competing in the French F4 Championship.[5] He would claim his first win in the series at the Hungaroring after overtaking polesitter Enzo Geraci, and holding the lead until the end of the race.[6] He would clinch a second victory later that season at Race 2 at Magny-Cours.[7]
2022
He returned to French F4 in 2022 for his sophomore season.[8] He would go on to win the championship, claiming five race wins.
Formula Regional European Championship
2023
In 2023, Giusti stepped up to the Formula Regional European Championship, driving for G4 Racing.[9][10] During race 1 at the Circuit Paul Ricard, he would achieve his maiden victory after starting from pole position.[11] His second win would come at the Red Bull Ring, coincidentally on his 17th birthday.[12] During the following race in Monza, Giusti would finish 3rd, but went on to inherit his third win after winner Andrea Kimi Antonelli and runner-up Marcus Amand were both penalized after the race.[13] He would go on to finish the season in 6th.
2024
For 2024 he remained in Formula Regional European Championship but he would switch to ART Grand Prix.[14] Giusti secured his first win of the season during a chaotic and rainy race 2 at Paul Ricard.[15] His next win came during another rainy race, this time in Imola. He started the race in 4th, and managed to maintain the lead throughout three different safety car appearances.[16][17]