Bernoldi started out in karting in 1986, and won many regional and national titles, before heading to Europe at age 16 to begin his car racing career. He entered the Formula Alfa Boxer series in Italy, where he finished fourth in his first race. Following a successful single entry in the Championnat de France Formule Renault, Bernoldi then entered the Eurocup Formula Renault 2.0 and won on his debut, the final round of the series. The following year he took in nine victories and the title, before entering British Formula 3 with the Promatecme team in 1997. Bernoldi took his first victory at Spa en route to fifth in the championship, and also finished third at that year's Macau Grand Prix. He remained with Promatecme for 1998 to take six more victories, but was only able to finish runner-up to compatriot Mario Haberfeld.
In 1999, Bernoldi progressed to the International Formula 3000 championship with the Red Bull Junior Team. Although his debut season only resulted in two points, he was retained by the team for the following year. Due to the team's links with Sauber, he tested for the Formula 1 team in both seasons, in addition to also testing for the Prost GP team in 2000. Although touted before the start of the 2001 season to be joining either Prost, Minardi or Sauber, Bernoldi instead signed a contract with Arrows, a move that was seen as surprising by some.
During 2001, Bernoldi performed respectably for the Arrows team, occasionally matching his more experienced teammate Jos Verstappen for pace. However, he gained notoriety for his efforts at the Monaco Grand Prix, where he held up the much faster David Coulthard for 35 laps; after a botched start, Coulthard had been fighting his way through the field, only to be stuck behind the Arrows, prompting irate responses from both Coulthard, and McLaren team principal Ron Dennis. Bernoldi was defended by his team boss Tom Walkinshaw, whom hit back at McLaren. He failed to score any points in 2001, with 10 retirements from 17 starts, his highest finish being an eighth at the German Grand Prix.
Despite Verstappen being the only Arrows driver to score points in 2001, Bernoldi was retained by Arrows for 2002, being partnered by Heinz-Harald Frentzen. At Sepang he notably overtook Michael Schumacher, having been passed by the German as he attempted to fight through the field after a first-lap incident with Juan Pablo Montoya, although his driving in that race was criticized by Allan McNish. Due to serious financial problems, Arrows were forced to withdraw three-quarters of the way into the 2002 season. He subsequently switched to the World Series by Nissan, after a potential drive for Jordan Grand Prix failed to materialize.
In his debut season in the World Series by Nissan, Bernoldi finished sixth in the championship, having won two races. He also participated in a "mega test", held by Alfa Romeo, with a prospect of driving for the team in the 2004 European Touring Car Championship season. Despite this test, he continued in the World Series in 2004, and finished third overall, with another pair of wins. In mid-2004 he was named a test driver for BAR, completing two tests at the Circuito de Jerez in Spain, in order to prevent the regular BAR drivers having to make several long-distance trips. He remained with the team after these sessions, also undertaking tests of BAR's "Concept Car" (a hybrid F1 car with a 2004 frontal setup mixed with a 2005 rear setup). He remained BAR's test driver for 2005, but began to look for pastures new in 2006, participating in less tests for the now-renamed Honda Racing F1 Team - although he did remain as official test driver. Although he impressed in Champ Car during a test for Rocketsports, his solitary race during 2006 came in Argentina's TC 2000 series. In 2007, Bernoldi competed in the Stock Car Brasil, competing in 11 of the 12 races and finishing 13th in the championship, with his best results being a pair of podium finishes.
For 2008 Bernoldi, signed a contract with Rocketsports for the 2008 Champ Car World Series. However, following the reunification of Champ Car and the Indy Racing League, Rocketsports withdrew, opting not to compete in the new, combined, series. It was later announced that Bernoldi would drive for Conquest Racing in the newly combined series' 2008 season. His best result was fourth, in the final Champ Car-sanctioned race at Long Beach. His best result in the reunified IndyCar Series was fifteenth at the 2008 Indianapolis 500. A collision with team-mate Jamie Camara at Watkins Glen lead him to publicly criticize the team, and speculation that he might leave them. A thumb injury ruled him out of the final two races of the season, his seat being filled by Alex Tagliani.
For 2009, Bernoldi was the full-time driver of Flamengo in the Superleague open wheel series and also he ran a partial schedule in Stock Car Brasil. He also competed in the FIA GT Championship for Sangari Team Brazil, taking his first win at Paul Ricard.
In 2010, he raced in the new FIA GT1 World Championship for Vitaphone Racing, scoring the pole position and winning his home race at Interlagos.
For 2011, he continued to race in the series, campaigning a Nissan GT-R for the Sumo Power GT team. He also entered four races of the GT Brasil, driving for Ford GT Racing Team BMG.
In 2012, he drove for Vita4One Team Italy in the Italian GT Championship, followed by appearances for AF Waltrip in the FIA World Endurance Championship, before making his debut in the International GT Open, driving once more for AF Corse in a Ferrari 458 GT2. He also made his debut in the SPEED EuroSeries, driving for Team JD in a Tatuus CN, whilst entering the 500 Milhas de Kart do Beto Carreiro at the end of the year. In 2013, he entered the International Challenge of the Stars, run by Felipe Massa.
(key) (Races in bold indicate pole position; races in italics indicate fastest lap.)
(key) (Races in bold indicate pole position)1 Run on same day.
2 Non-points paying, exhibition race.
(Races in bold indicate pole position) (Races in italics indicate fastest lap)
† Ineligible for championship points.