Grosjean won all ten rounds of the 2003 Formula Lista Junior championship and then dominated the French Formula Renault Championship in 2005 with ten victories. He joined the Renault Driver Development programme and competed in the Formula 3 Euro Series, winning the championship in 2007 with the ASM team after battling Sébastien Buemi for the title. He moved to the GP2 Series with ART in 2008, finished fourth in his rookie season, and won the GP2 Asia Series. He won the GP2 title in 2011 with DAMS after returning from a brief Formula One debut.
Grosjean debuted in Formula One mid-season with Renault in 2009, replacing Nelson Piquet Jr. following the Crashgate controversy. He struggled throughout the truncated campaign and lost his seat for 2010, spending that year winning the Auto GP Series with DAMS and scoring FIA GT1 victories. He won the 2011 GP2 championship to earn his return to Formula One.
Grosjean joined Lotus alongside 2007 champion Kimi Räikkönen for 2012. He scored his first podium at the Bahrain Grand Prix — the first Formula One podium for a French driver since Jean Alesi in 1998 — and added further podiums in Canada and Hungary. However, at the Belgian Grand Prix he caused a multi-car collision at the start, eliminating Hamilton, Alonso, and Pérez among others. The stewards imposed a one-race ban, the first in Formula One since Michael Schumacher's in 1994. He served the ban at the Italian Grand Prix.
Despite the controversies, Grosjean developed into one of the grid's more consistent performers. In 2013 he took six podiums and finished a career-best seventh in the World Drivers' Championship, producing standout performances at Japan and India. He remained with Lotus through 2015, recording his final F1 podium at the Belgian Grand Prix that year after Vettel's tyre failure promoted him into the points.
Grosjean moved to the newly formed Haas F1 Team for 2016 and finished sixth on the team's debut race in Australia, scoring Haas's first-ever points and winning Formula One's inaugural Driver of the Day award. He partnered Kevin Magnussen from 2017 onwards. His best Haas result was fourth at the 2018 Austrian Grand Prix.
The 2020 season ended in catastrophe at the Bahrain Grand Prix. On the opening lap, Grosjean's Haas VF-20 made contact with Daniil Kvyat's AlphaTauri and hit the barrier at high speed, splitting the car at 67 g. The front half was wedged into the barrier while fuel ignited immediately. Grosjean exited the burning wreck unaided after 28 seconds. He suffered second-degree burns to his hands and ankles, was airlifted to hospital, and missed the final two races of the season. The halo device, introduced in 2018, was universally credited with deflecting the barrier away from his head.
Grosjean moved to the IndyCar Series in 2021 with Dale Coyne Racing on a partial schedule limited to road and street courses, choosing not to race on superspeedways. He adapted quickly: at the first race on the Indianapolis Motor Speedway road course, he earned his first IndyCar pole position — his first pole since a GP2 race in 2011 — and finished second to Rinus VeeKay. He recorded three podiums across the season and nearly matched IndyCar Rookie of the Year winner Scott McLaughlin in points.
He raced with Andretti in 2022 and 2023, adding further podiums, before a season with Juncos Hollinger in 2024. After a year in IMSA sportscars with Lamborghini in 2025, Grosjean returned to IndyCar full-time for Dale Coyne Racing in 2026.