[2][3][4] In 2024, Guintoli was contracted as a test rider, together with Bradley Smith, for the BMW Motorrad world superbike team, delivered by Shaun Muir Racing.

In 2021 he was the winner of the 24 Hours of Le Mans endurance race on Suzuki together with Xavier Simeon and Gregg Black,[6] followed by the Bol d'Or and finally the Championship.

[7] In 2022, he suffered a wrist injury preventing his entry into the Suzuka 8 Hours race and also as a replacement for Joan Mir in MotoGP.

[8][9] Guintoli made his grand prix debut in the 250cc class for the Équipe du France, partnering Julian da Costa for the French GP, with a Honda.

[10] Guintoli joined the French team Équipe du France - Scrab GP with fellow Frenchman Randy de Puniet in 250 Grand-Prix.

He even scored his first podium at Assen, finishing third in wet conditions, not far behind than race-winner Anthony West and Franco Battaini, both in Aprilias.

For the 2005 season, Guintoli returned to the Équipe du France GP Scrab, partnered first by Grégory Leblanc and then by Mathieu Gines, both French.

He was confirmed by the French team Equipe du France GP Scrab also for 2006, with rookie Jules Cluzel as his partner.

[12] The Tech 3 team was one of the backmarkers and Guintoli has scored solid lower-order points in 2007, always qualifying in front of his teammate Makoto Tamada and the Kawasakis.

At the end of the season Alice Team did not renew Guintoli's contract and with no other seats free he was forced to leave MotoGP to find a ride.

Guintoli then took a step down to the British Superbike Championship for the 2009 season, riding for the Worx Crescent Suzuki team as their sole rider.

[13] Guintoli started his debut season in the British Superbike Championship impressively with a 1st and 2nd at the Brands Hatch Indy circuit.

The incident left Guintoli with a broken tibia and fibula in his right leg, with him expected to miss several rounds He finished the season in 8th place, with 166 points, having scored one win and three further podiums in his first four races.

He skipped two rounds mid-season, having re-joined part-time the MotoGP class after six years to replace the injured Alex Rins, again for Suzuki.

[16] Guintoli then rode the final World Superbike Championship round of the 2009 season in Portimão finishing tenth in the second race.

He joined the Aprilia factory team in 2013 as a replacement for Max Biaggi,[20] taking one win and finishing third overall in the Championship behind Tom Sykes and Eugene Laverty.

For the EWC 2021 season, Guintoli was part of the Championship-winning team with Gregg Black and Xavier Siméon riding for Yoshimura-Sert Suzuki.