Gené began karting aged thirteen, winning both the Catalan and Spanish National Class Kart Championships in 1988. He was also the youngest driver to win the Senior Class of the Spanish Kart Championship, doing so in 1990. Moving to car racing, he finished runner-up in the 1993 European Formula Ford Championship and took second at the Formula Ford World Cup and Festival. He was named Rookie of the Year in the 1994 British Formula 3 Championship.
Gené won the FISA Superformula championship in 1996 and then took the Open Fortuna by Nissan Championship in 1998 with six wins and three pole positions, establishing himself as a strong single-seater prospect heading into Formula One.
Gené joined Minardi for 1999 in what proved a difficult but ultimately rewarding debut season. After several ninth and eighth-place finishes, he scored the defining result of his Formula One career at the European Grand Prix at the Nürburgring — a sixth-place finish that gave him his sole championship point and ended Minardi's four-year points drought dating back to 1995. His teammate Luca Badoer was denied a potential points finish in the same race when his gearbox failed.
Gené returned to Minardi for 2000 but failed to score, with his best results being eighth place at the Australian and Austrian Grands Prix.
Unable to secure a competitive race seat for 2001, Gené signed with Williams as a test driver. He drove three race weekends as a substitute for Ralf Schumacher: at the 2003 Italian Grand Prix, where Schumacher was unable to start due to concussion and Gené finished fifth to score four points; and at the 2004 French and British Grands Prix after Schumacher sustained a back injury at the United States Grand Prix. He subsequently lost the 2004 race seat to Antônio Pizzonia.
In November 2004, Gené signed with Scuderia Ferrari as a test driver alongside Luca Badoer. His contract was renewed for 2007, though reduced testing regulations in Formula One from 2007 and 2008 limited his track time with the team. He was replaced at the end of 2010 by Jules Bianchi.
Gené accumulated 36 Formula One starts, scoring five championship points, with his best championship position being seventeenth in 2003 and his best race finish fifth at the 2003 Italian Grand Prix.
Peugeot hired Gené as a factory driver for their 908 HDi FAP programme in the Le Mans Series from 2007. He crashed heavily in practice for the 2008 24 Hours of Le Mans, suffering a broken toe, but returned in 2009 without incident. Sharing a Peugeot 908 with David Brabham and Alex Wurz, Gené completed the final stint and brought the car home to victory, completing 382 laps to end Audi's recent dominance of the race. He also won the 1000 km Spa in 2008 driving for Peugeot.
From 2010, Gené served as a Formula One race commentator for Spanish television on Antena 3. In 2013 he became an expert analyst for Sky Sport F1 HD in Italy. He remains associated with Ferrari as a brand ambassador.
Gené's career encompasses the breadth of roles available to a driver of consistent competence in the modern era — race driver, test driver, factory sportscar driver, and media expert. His Le Mans victory in 2009, completed in the final stint as Peugeot ended Audi's run of dominance, stands as the most celebrated moment of his career. His single Formula One championship point for Minardi in 1999 nonetheless remains historically significant as the team's first points finish in four seasons.