Trulli's parents were motorsport enthusiasts who named him after Finnish motorcycle racing champion Jarno Saarinen, who was killed at Monza in 1973. He began karting at an early age and won the Karting World Championship in 1991, going on to claim the Italian karting championship and multiple titles in various categories through 1995. He then won the German Formula Three Championship in 1996, setting up his Formula One graduation.
Trulli debuted with Minardi in 1997 before replacing the injured Olivier Panis at Prost mid-season. He impressed immediately, finishing fourth in Germany and leading briefly at Austria before an engine failure ended his race. He remained at Prost for the following two seasons, scoring his first podium in wet conditions at the 1999 European Grand Prix, though the poor competitiveness of the Prost car eventually drove him to seek a move.
At Jordan, Trulli failed to add to his podium tally but regularly produced exceptional qualifying laps that placed his car well ahead of where pure pace suggested it should be. Managed by Flavio Briatore, he secured a deal with the Renault-aligned Benetton team for 2002.
Trulli partnered Jenson Button at Renault in 2002, frequently outqualifying his teammate. When Button departed, Trulli stayed alongside promoted test driver Fernando Alonso in 2003. The Renault proved competitive in Alonso's hands with a win in Hungary, while Trulli added a podium in Germany.
In the first half of 2004 Trulli was arguably the stronger Renault driver, accumulating points and podiums. He converted pole position into victory at Monaco in a display of controlled brilliance, giving him the only Grand Prix win of his career. However, his relationship with team boss Briatore deteriorated after an error in France allowed Rubens Barrichello onto the podium. Trulli was sacked with three races remaining despite leading his teammate in the championship, and he moved to Toyota for the final two rounds of that season.
Trulli delivered consistent results for Toyota, including an early 2005 pole at Indianapolis, though that race was boycotted by the Michelin-shod teams over tyre safety concerns. He regularly matched or outperformed his highly-paid teammate Ralf Schumacher.
The 2009 season brought one of his most controversial moments. In Australia, after the Toyotas started from the pit lane following a qualifying disqualification, Trulli finished third but was penalised 25 seconds for passing Lewis Hamilton under a safety car. The penalty was later overturned when Hamilton admitted he had deliberately let Trulli pass under team orders — information his team had initially concealed from the stewards, leading to Hamilton's disqualification from the race result. At Bahrain, Trulli qualified on pole but finished third due to an unconventional tyre strategy; he recorded the fastest lap, the only time he achieved that distinction in his career. At the Japanese Grand Prix, which proved to be Toyota's final home race, he qualified and finished second.
After Toyota withdrew from Formula One at the end of 2009, Trulli signed with the newly formed Lotus team alongside Heikki Kovalainen. The team operated on a limited budget as one of three new entrants and rarely featured at the sharp end of the grid. Team Lotus (as it was renamed for 2011) retained Trulli for the following season, but he was released before the 2012 campaign when the team, by then renamed Caterham, signed Vitaly Petrov. His departure left Formula One without an Italian driver for the first time since 1969, a gap that lasted until Antonio Giovinazzi competed at the 2017 Australian Grand Prix.
A phenomenon closely associated with Trulli was the so-called "Trulli Train" — a term that entered common usage in the mid-2000s. His ability to generate outstanding qualifying laps in cars of only middling competitiveness, combined with a highly effective defensive driving style once the race began, regularly produced long queues of faster cars unable to pass him. The combination made him one of the most discussed and divisive drivers of his era: respected for his technical precision but sometimes criticised for a perceived inability to match his grid positions with race results.
Trulli competed in the inaugural FIA Formula E season (2014-15) with his own Trulli GP team in partnership with Drayson Racing Technologies and Super Nova Racing. The team withdrew after failing scrutineering of their new drivetrain ahead of the 2015-16 campaign.
Outside motorsport, Trulli co-owns a vineyard in the Abruzzo region of Italy and produces his own wine. His son Enzo Trulli, named after Jarno's own father, pursued a karting career before moving into single-seater competition.