Rangoni's racing career began in karts, where he spent four years before transitioning to circuit competition. He made his single-seater debut in the 1989 Italian Formula Alfa Boxer Championship, finishing sixth in the points standings. He then spent two seasons in the Italian F2000 Trophy, claiming the title in his second year in 1991.
In 1993, Rangoni entered the Italian Formula Three Championship, and he won the title in 1995 driving a Dallara-Fiat. That success earned him a place in the 1996 FIA International F3000 Championship, though he entered only one round, the race at Pau, where he finished sixth and ended the season seventeenth in the overall standings. After this brief F3000 campaign, Rangoni stepped away from racing following a family tragedy.
Rangoni returned to competition in 1999, switching to touring cars with the Renault Sport Clio International Trophy. He quickly found his form in the category, achieving an extraordinary run of four consecutive championships from 2000 through 2003 — a period of dominance that established his reputation as one of the leading touring car drivers in the Italian racing scene.
In 2004, Rangoni graduated to the FIA European Touring Car Championship, driving an Alfa Romeo 156. He finished the series sixteenth overall. He returned to international touring car competition in 2006 under the renamed FIA World Touring Car Championship banner, joining Proteam Motorsport in a BMW 320i. That season he claimed a podium finish in Valencia and finished nineteenth overall, also placing second in the Yokohama Independents Trophy behind Tom Coronel, with two Independents wins to his credit.
Rangoni continued with Proteam Motorsport in 2007. He moved up to fourteenth overall in the championship standings and secured another outright podium, finishing one place ahead of works BMW driver and fellow Italian Alessandro Zanardi in the Independents standings. Despite winning nine times in the Independents classification — including double-points victories at Macau — he narrowly lost the Yokohama Independents Trophy to Stefano D'Aste by just two points; D'Aste had scored three wins to Rangoni's nine, but the scoring system favoured consistency over the season.
In 2008, Rangoni expanded his programme, racing in the Italian Porsche Carrera Cup where he finished as runner-up, and also participating in the Superstars Series. His campaign in the Porsche championship demonstrated his adaptability across different car categories, adding a GT dimension to a career that had ranged from open-wheel formula racing to front-wheel-drive touring cars.
Rangoni's career arc — from karts through Italian formula racing, a title at Italian F3 level, and then sustained success in touring cars culminating in WTCC competition — reflects the varied pathways common among Italian club and international racing drivers of his generation. His four Clio Cup titles remain the centrepiece of his record, while his WTCC seasons with Proteam Motorsport gave him experience at the highest level of touring car competition against factory-supported entries. His near-miss in the 2007 Independents Trophy, with nine wins still insufficient to clinch the title, stands as one of the more striking statistical anomalies of that era in WTCC Independents competition.