De Puniet entered competitive motorcycle racing at a young age, winning the French 125cc Championship in 1998 — his debut season in that class. He stepped up to the full World Championship the following year, moving through the junior ranks before graduating to the 250cc World Championship in 2001.
The 250cc class became the foundation of de Puniet's reputation as a race winner. Two podium finishes in 2002 secured him a factory Aprilia contract for 2003, and he responded by taking his first Grand Prix victory at the Circuit de Catalunya. He finished fourth in the 2003 standings with three wins in total. In 2004 he achieved third place in the championship, recording one further win. A season with Jorge Martínez's Aspar Team on an Aprilia followed in 2005 before he made the transition to MotoGP.
De Puniet joined the Kawasaki factory team for the 2006 MotoGP season, remaining with the Japanese manufacturer through 2007. At the 2007 Catalan Grand Prix he took his first front-row grid position, and a wet-weather race at the Motegi circuit produced a second-place finish — his best result in the premier class to that point.
From 2008 to 2010 he raced for LCR Honda. The 2010 campaign opened promisingly, with consecutive front-row starts at Silverstone and Assen leaving him fifth in the championship standings, before a leg fracture sustained at the Sachsenring in Germany ended his challenge. He recovered to finish the season, but the consistency needed for a title bid was lost.
After that season, de Puniet moved to the Pramac Ducati satellite team in 2011, then joined the Power Electronics Aspar squad in 2012, where he raced a modified Aprilia RSV4 known as the ART machine under the championship's Claiming Rules Team regulations. By 2014 he had transitioned into a development and testing role for Suzuki's 2015 MotoGP project, making a single wild-card appearance at the season finale in Valencia.
De Puniet attempted a return to full-time competition in the 2015 Superbike World Championship but struggled to make an impact. He subsequently turned to the FIM Endurance World Championship, competing with Moto Ain in 2021, adding long-distance racing to a CV that had been built almost entirely in sprint formats.
In the years following his endurance campaign, de Puniet competed in the MotoE World Cup, riding an Energica Ego Corsa electric motorcycle — a departure that signalled his engagement with the emerging electric side of Grand Prix racing.
Throughout his career de Puniet accumulated the lived experience of navigating multiple classes and manufacturer programmes across nearly two decades of professional racing. He is a member of Champions for Peace, a group of elite athletes assembled by Peace and Sport, the Monaco-based international organisation operating under the patronage of H.S.H. Prince Albert II of Monaco.
De Puniet's move into endurance racing with Moto Ain in 2021 reflected a pattern common among veteran road racers transitioning toward the longer-format events that the FIM Endurance World Championship offers, using established racecraft and tyre-management skills developed over a career at the highest level of international motorcycle competition.