Despite his famous lineage, Prost did not begin racing until the relatively late age of 22, starting in Formula Campus. He attended Columbia University in New York, where he also excelled as a golfer. He was born two days after his father competed in the 1981 Austrian Grand Prix.
Prost entered the Spanish Formula Three Championship in 2006 with Racing Engineering, winning one race and collecting six podiums to finish fourth in the championship and earn the best rookie award. He returned in 2007 to finish third, adding two wins, a pole position, and seven podiums. The following year he moved to the Euroseries 3000, competing for Bull Racing, and won the championship in his debut season with one win, two poles, and seven podiums.
He also raced in the A1 Grand Prix as a driver for Team France across the 2007–08 and 2008–09 seasons, beginning as a rookie representative before being promoted to race driver toward the end of the second campaign.
Prost built the core of his professional reputation in endurance racing. His Le Mans debut came in 2007 with Team Oreca in a Saleen S7-R, finishing fifth in class. He progressed to the LMP1 category in 2009 with Speedy Racing Team Sebah, delivering a strong personal performance before a gearbox failure dropped the car down the order.
From 2010 onward, Prost raced for Rebellion Racing alongside Swiss driver Neel Jani. In 2011, the pair finished sixth overall and first in the unofficial petrol class. The 2012 race saw Prost, Jani, and Nick Heidfeld take fourth place in LMP1 in their Lola B12/60 Coupe Toyota, completing 367 laps.
In the FIA World Endurance Championship in 2012 and 2013, Prost and Jani were dominant in the LMP1 privateer category, winning nine races across the two seasons. Moving to the new Rebellion R-One in 2014, Prost won the first four races of the season in the LMP1-L category and clinched the privateer title. The 2014 24 Hours of Le Mans brought him a class victory alongside Nick Heidfeld and Mathias Beche.
In North American endurance racing, Prost claimed back-to-back victories at Petit Le Mans in 2012 and 2013, and finished third at the Sebring 12 Hours in 2013.
Prost proved equally dominant in ice racing. During the 2009–10 Andros Trophy winter series, he competed in the electric car category and won the championship with five poles, six wins, and eighteen podiums from 21 races. He successfully defended the title the following winter. In 2011–12, he joined his father in the works Dacia team and won the rookie title in the main series.
Though Prost never raced in Formula One, he maintained a long-running connection with the Lotus Renault program. He drove a Renault F1 car for the first time at Magny-Cours in 2010, impressing the team with his pace. He served as a test and development driver for Lotus from 2011 through 2014, taking part in young driver tests at Abu Dhabi and Silverstone. At the 2013 Silverstone rookie test, he posted the fastest lap among all rookie participants.
On 30 June 2014, Prost signed with e.dams Renault for the inaugural FIA Formula E season. He made immediate history at the first race in Beijing, becoming the first driver in the series to claim a pole position. He led that race until a final-lap incident with Nick Heidfeld ended his hopes of a debut victory, and he was given a ten-place grid penalty for the next round.
Prost took his first Formula E win in Miami and finished the inaugural season sixth in the standings. His best championship result came in the 2015–16 season, when he finished third in the final standings. He remained with the series through the 2017–18 season before stepping away from Formula E.
Nicolas Prost carved out a career defined by consistent high-level endurance racing performance rather than a breakthrough in top-tier single-seaters. His class victory at the 2014 24 Hours of Le Mans, nine WEC privateer wins across two seasons, and back-to-back Petit Le Mans victories represent a meaningful body of work independent of his famous surname. His role as one of Formula E's founding competitors — claiming the series' first-ever pole position — also places him in an important chapter of electric motorsport history.