Piquet was born in Heidelberg while his father was still competing in Formula One. His parents separated shortly after his birth, and he lived in Monaco with his Dutch mother, Sylvia Tamsma, until the age of eight, when he moved to Brazil to live with his father. He attended the American School of Brasília and began karting in 1993, remaining in Brazilian karting through 2001.
Piquet moved to Formula Three Sudamericana in 2001, winning the championship in 2002 with his own Piquet Sports team. He joined the British Formula 3 Championship in 2003, finishing third with six wins. In 2004 he won the British Formula 3 Championship outright, becoming at the time the youngest driver to have won that title, at nineteen years and two months. A test with Williams followed.
In 2005 Piquet drove in the A1 Grand Prix for Team Brazil, winning the Sprint and Main races at the opening round at Brands Hatch. He also entered the GP2 Series with Hitech Piquet Sports, claiming his first GP2 victory at Spa-Francorchamps. In 2006 he finished runner-up in the GP2 Series behind Lewis Hamilton in his second year in the championship.
Piquet served as Renault's test and reserve driver throughout 2007. For 2008 he was promoted to a race seat alongside Fernando Alonso, reportedly preferred over Heikki Kovalainen because Kovalainen was seen as a potential in-team rival to the double world champion.
His first Formula One season produced mixed results. He scored his first championship points with a seventh-place finish at the 2008 French Grand Prix, passing Alonso in the closing laps. At the 2008 German Grand Prix he claimed his only F1 podium, finishing second to Lewis Hamilton. He also placed fourth at the Japanese Grand Prix. However, crashes at Monaco and Canada, combined with consistent pressure from the team, kept him under threat throughout the year.
Piquet started 2009 poorly, failing to progress beyond Q1 in the first three races and scoring no points across the first half of the season. On 3 August 2009, Renault confirmed he had been dropped; Romain Grosjean replaced him for the remainder of the year.
In August 2009, following his departure from Renault, Piquet made a statement to the FIA alleging that he had been ordered by team principal Flavio Briatore and engineer Pat Symonds to crash deliberately at the 2008 Singapore Grand Prix. The crash triggered a safety car period at a moment strategically advantageous to Alonso, who went on to win the race from an unlikely position. In exchange for his testimony, the FIA granted Piquet blanket immunity from sanction.
On 21 September 2009, after Renault declined to contest the FIA charges, Briatore and Symonds left the team. Piquet stated publicly: "I bitterly regret my actions to follow the orders I was given... My situation at Renault turned into a nightmare." Renault initially accused Piquet of false allegations, but in December 2010 a UK court found in the Piquets' favour: Renault apologised, acknowledged the allegations were not false, and paid substantial damages.
Crashgate ended Piquet's Formula One career. Despite interest from several teams and public encouragement from F1 chief executive Bernie Ecclestone, no drive materialised, and Piquet moved to NASCAR for 2010.
Piquet competed extensively in American stock car racing. In 2012 he won the NASCAR Nationwide Series race at Road America — the first Brazilian driver to win a NASCAR national touring series event — and added two wins in the Camping World Truck Series later that year, at Michigan and Las Vegas. He drove part-time in the Sprint Cup Series at Watkins Glen in 2014. He finished seventh in the 2012 Truck Series standings overall and was a contender for Rookie of the Year in the 2013 Nationwide Series.
He also contested the 2014 Global RallyCross Championship, collecting four podiums and finishing fourth.
In August 2014 Piquet signed with China Racing (later NEXTEV) for the inaugural Formula E season. His consistent results across the 2014–15 campaign — including victories at Long Beach and Moscow — earned him the championship title by a single point over Sébastien Buemi, making him the inaugural Formula E champion. He joined Panasonic Jaguar Racing for 2017 but struggled for results across two seasons before leaving the team mid-2019.
Piquet's career presents a stark contrast: genuine talent — two British F3 titles, a GP2 runner-up finish, an F1 podium, and a Formula E championship — set against the shadow of Crashgate, one of the most significant scandals in motorsport history. His willingness to come forward as a witness proved instrumental in exposing institutional wrongdoing at Renault, even as it permanently closed the door on his return to Formula One.