Badoer was born in Montebelluna, Veneto, Italy. He raced karts in his youth starting in 1985 and scored two wins. In 1986, Badoer drove in the 100cc category to become the karting champion of Venice and became national champion the following year. He won the Italian championship in the 100cc international class in 1988.

In 1989, Badoer moved to single-seater racing, joining the Trivellato team in the Italian Formula Three Championship driving a Dallara/Alfa Romeo that followed a move to MRD in 1990. Driving a Ralt RT33 Alfa Romeo, he defeated Alex Zanardi and Roberto Colciago to win the final race of the 1990 season and finished 10th in the championship. In 1991 he moved to the Supercars team driving a Dallara 391 Alfa Romeo to win four races in succession, but was disqualified after a technicality concerning his tyres. Badoer finished 4th overall taking 33 points. For 1992 he was picked to drive by Crypton Engineering for the Formula 3000 Championship, in which he emerged as champion, winning four races en route to the title.

His debut Formula One season in 1993 was mired by BMS Scuderia Italia’s uncompetitive Lola chassis, which, despite Ferrari engines, was the slowest car in the championship in terms of qualifying pace. In South Africa, Badoer retired after 20 laps due to gearbox failure. In Brazil, Badoer qualified 21st and finished 12th after an incident forced him to pit for a new nose cone. At Donington, he fell victim to a new rule limiting qualifying to the fastest 24 cars (his time was only good enough for 26th). The round at Imola saw Badoer race as high as sixth, but finish seventh. This remained Badoer’s best result in Formula One. In Spain, he was unable to finish and at Monaco, Badoer finished the last of the runners. He managed to finish 15th in Canada. At Magny-Cours, Silverstone, Hockenheim and Budapest, Badoer failed to finish, twice to suspension failure. Going into Spa, the Lola team was gaining reliability and Badoer finished 13th. At his home race at Monza he was ahead of Christian Fittipaldi and battled for several laps before the Brazilian hit Badoer’s car and eventually finished 10th. At Estoril, Badoer finished 14th after starting last. After the race, Lola did not travel to the races in Japan and Australia after the team announced they were to merge with Minardi in 1994.

In 1996 he switched to Forti Corse to be teammates with Andrea Montermini after Pedro Diniz left to join Ligier. During the season, he was only able to qualify for six of the ten races the team entered. In the 1996 Argentine Grand Prix Badoer was involved in a heavy collision with Diniz, whose Ligier struck him from behind and flipped his Forti upside down. He emerged from the collision unhurt but Argentine safety marshals were heavily criticised for failing to assist Badoer in a timely manner because they feared a fire would break out. At Imola, Badoer had a newer car and outqualified Montermini by more than a second. He finished 10th and the last of the runners. In Monaco, Badoer remained at the back and collided with Jacques Villeneuve at Mirabeau forcing both drivers to retire. He did not qualify in Spain but started 20th in Canada. In France, Badoer started ahead of Eddie Irvine after the Ferrari was relegated to the back. Forti Corse folded after that year’s British Grand Prix.

In 1997 Badoer moved to the new FIA GT Championship, driving a Lotus Elise GT1 for GBF Engineering with codriver Mimmo Schiattarella. At Hockenheim and Silverstone, Badoer retired with his form improving in Helsinki where he finished 20th. Schiattarela and Badoer retired in Nurburgring and Zeltweg with the pair finishing 12th at Donington completing 151 laps. A race at Mugello saw Badoer retire with loose bodywork. While driving for GBF, Badoer was hired as Scuderia Ferrari’s test driver, a role he maintained until 2010.

Badoer returned to Formula One racing in 1999, again with the Minardi team. At Melbourne, Badoer raced as high as fifth at some point until gearbox problems forced him to retire with 15 laps to go. Prior to Brazil, he suffered a testing accident which left him with a broken hand. Stéphane Sarrazin took his seat for the race. He returned for Imola with his hand still causing problems but managed to finish eighth. He suffered from gearbox problems and a spin in Monaco and Spain. In July, Ferrari’s number one driver Michael Schumacher broke his leg in an accident at the British Grand Prix at Silverstone. As Ferrari’s test driver, Badoer expected to be promoted to the race seat in Schumacher’s absence, but the team opted for Mika Salo instead, prompting criticism from former Ferrari driver Jean Alesi, who had himself turned the position down. His best chance to score points came at the chaotic 1999 European Grand Prix, only for gearbox failure to take him out 13 laps from the end when he was running in fourth position; teammate Marc Gené was promoted to sixth as a result (he would finish there to score the point widely believed to be the deciding factor in the 1999 Drivers’ Championship, holding off Ferrari’s Eddie Irvine after McLaren’s Mika Häkkinen had passed him following a car failure that took Jacques Villeneuve out from fifth position). Badoer was so upset he broke down in tears after climbing out of the car.

Unable to find a satisfactory race seat in Formula One after 1999, Badoer focused on his job as the permanent test driver for Ferrari, covering thousands of kilometres at the Mugello and Fiorano test circuits each year. He is credited with making a vital contribution to Ferrari’s first Formula One Drivers’ Championship win for 21 years in 2000.

In racing at Valencia, Badoer became the first Italian to drive for Ferrari in 15 years. BBC commentator and former F1 driver Martin Brundle argued in The Sunday Times that the inclusion of Badoer and Romain Grosjean in the race was dangerous, since new rules that ban further testing until 1 January 2010 mean that they have been unable to gain the experience necessary to race. Badoer had never driven the Ferrari F60 before, having last tested the Ferrari F2008 at the Autódromo Internacional do Algarve in Portimão, Portugal in December 2008.

On 11 August 2009 it was confirmed that Badoer would return to Formula One racing after almost 10 years, to replace the injured Felipe Massa at the 2009 European Grand Prix in Valencia. Massa was injured during the qualifying session for the 2009 Hungarian Grand Prix when a piece of suspension fell from the rear of Rubens Barrichello’s Brawn GP car and struck Massa’s helmet, fracturing his skull, knocking him unconscious and causing him to crash into a tyre wall. Michael Schumacher was set to replace Massa, but a neck injury Schumacher sustained in a German superbike test earlier in the year forced him to pull out. Ferrari confirmed that Badoer (Ferrari’s longest-serving test driver) would replace the injured Massa instead. The BBC reported that Badoer was given the job as a “thank you for his commitment to the team”. His previous Formula One appearance was in the 1999 Japanese Grand Prix, where he qualified last and retired late in the race. While Badoer had waited almost 10 years since his last drive, this gap is shorter than the 10 years and three months between Jan Lammers’s appearances at the 1982 Dutch Grand Prix and the 1992 Japanese Grand Prix.

At the end of 2010, Badoer retired from Ferrari as test driver and was replaced by Jules Bianchi. He ended his 12-year role at Ferrari with a demonstration of the Ferrari F60, the car Badoer raced in 2009 on a Ferrari-themed day at the Bologna Motor Show on 8 December 2010. He also took part in a forum for Gazzetta dello Sport, where he stated his only regret was that he “was only able to do two races [for the Scuderia]”. In January 2011, Badoer drove the Ferrari F60 with a special livery on the ice of the Madonna di Campiglio for his final act with the team.