Gené won the Spanish Karting Championship in 1986 before moving into automobiles. He demonstrated immediate speed, claiming the Fiat Uno Championship in 1987 and the Spanish Formula Ford Championship in 1988. In 1989 he relocated to England to compete in the British Formula Ford Championship and participated in the Formula Ford Festival, finishing fourth. Moving up to British Formula 3, he spent two seasons in the series and finished fourth in the 1991 championship with West Surrey Racing in a Ralt-Honda. He attended the prestigious Marlboro Masters at Zandvoort, where he was narrowly beaten by David Coulthard, and won the Fuji Superprix at the end-of-season Asian swing.
Backed by Marlboro sponsorship, Gené entered Formula 3000 in 1992 with Pacific Racing alongside Laurent Aïello. He won the opening round at Silverstone and finished fifth in the championship in his Reynard-Mugen. In 1993 he was involved with the Bravo F1 project, an attempt by former Spanish Formula One driver Adrián Campos to establish a national Formula One team. The project was abandoned following the sudden death of team owner Jean Mosnier and the car's failure to pass mandatory crash tests, though the team did appear at the 1993 South African Grand Prix. Gené returned to Formula 3000 that year with TWR Jr. without scoring points, and tried once more in 1994 with Nordic Racing on a Lola chassis while also serving as a Benetton test driver, a role that arose from his Walkinshaw connection.
Unable to secure a Formula One race seat, Gené returned to Spain and joined the Campeonato de España de Turismos. In 1995 he drove an Opel Vectra as an Opel works driver, finishing second in the championship. A switch to Audi in 1996 brought him the title after five victories.
His strong results led to a place in Roberto Ravaglia's BMW Team Italy-Spain for the 2002 European Touring Car Championship, finishing eighth overall in a BMW 320i. He then joined SEAT's ETCC campaign in 2003. After a difficult opening season in 17th place, 2004 brought two podium finishes and eighth overall.
When the ETCC evolved into the World Touring Car Championship in 2005, Gené continued with SEAT Sport. He began the season in the SEAT Toledo and took a victory late in the year with the new SEAT León, finishing 11th in the championship. He remained a SEAT factory driver through five further seasons, establishing himself as a reliable points scorer and occasional podium finisher.
In the 2009 WTCC season Gené collected two podiums from the opening Race of Brazil. He scored another podium at the Race of Morocco, passing teammate Yvan Muller on the final lap of race one. That season also included a series of incidents: he was caught in a first-corner pile-up triggered by Augusto Farfus at the Race of the Czech Republic, and had all his qualifying times disallowed at the Race of UK after a disconnected engine speed sensor was discovered in his car's data logging system.
Following SEAT Sport's withdrawal from the works programme at the end of 2009, Gené joined the SEAT-supported SR-Sport team run by SUNRED Engineering for 2010 alongside Gabriele Tarquini, Tiago Monteiro, and Tom Coronel. He took what appeared to be a victory at the Race of Belgium but was subsequently disqualified for a technical infringement, handing the win to Tarquini. He was replaced at the Race of Japan by Michaël Rossi and finished the season twelfth in the championship standings.
Gené entered the 24 Hours of Le Mans as a sideline to his touring car career, racing in the LMP675 category with a Volkswagen-powered Reynard for Noel Del Bello's ROC team from 2000. In 2001 he and the team achieved a class win at Le Mans and finished fifth overall, while also winning the 500km Most in the LMP675 class of the European Le Mans Series. That year he added a 24 Hours of Barcelona victory driving a Volkswagen Golf. In Spanish GT competition Gené won the title in 2003 co-driving a SEAT Toledo GT with Gines Vivancos.
In 1998 Gené accepted an invitation to drive the Cepsa MAN in the European Truck Racing Cup for team owner Manuel Santos Marcos. He spent two seasons in truck racing before returning to car competition full-time in 2000.
Gené moved to the Scandinavian Touring Car Championship in 2012 driving a Volkswagen Scirocco for Volkswagen Team Biogas. His best result was a second place at Åre Östersund Airport; he finished seventh in the championship while his teammate Johan Kristoffersson claimed the title. He subsequently competed in the TCR International Series and the World Touring Car Cup before stepping back from top-level competition.