Sargeant was born on December 31, 2000, in Fort Lauderdale, Florida. He is the nephew of shipping magnate Harry Sargeant III and the younger brother of former NASCAR driver Dalton Sargeant. He began karting in 2008 and competed in regional and national Rotax events before moving to Europe. In 2015 he won the CIK-FIA World KFJ Championship, becoming the first American to claim an FIA Karting World Championship since Lake Speed in 1978. He secured a senior karting title at the 2016 WSK Champions Cup.
Sargeant made his single-seater debut in the 2016-17 Formula 4 UAE Championship with Team Motopark, finishing second in the standings behind teammate Jonathan Aberdein after 15 podiums from 18 official races. In 2017 he moved to the F4 British Championship with Carlin, taking two wins at Rockingham and Silverstone among ten podium finishes and finishing third behind Oscar Piastri and dominant champion Jamie Caroline.
In 2018 Sargeant competed in the Formula Renault Eurocup with R-ace GP. He won the season-opening race at Paul Ricard and added victories at the Nurburgring and the season finale at Barcelona. He finished fourth in the championship on 218 points, behind Yifei Ye, Christian Lundgaard, and champion Max Fewtrell.
Sargeant returned to Carlin for the 2019 FIA Formula 3 Championship. He scored points on four occasions with a best of eighth, ending the season nineteenth with five points. At the end-of-year Macau Grand Prix he finished third behind Juri Vips and winner Richard Verschoor.
For 2020 he joined Prema Racing alongside Frederik Vesti and Oscar Piastri. Sargeant took multiple podiums and victories, including back-to-back wins from pole at Silverstone, and led the championship going into the final rounds. However, collisions at Monza left him without points in either race there, and contact on the opening lap of the final race at Mugello eliminated him as Piastri clinched the title by a single point. Sargeant finished third in the championship.
In 2021 he returned to FIA Formula 3 with Charouz Racing System after ruling out a Formula 2 move. He scored Charouz's first-ever podium in Formula 3 at the Hungaroring and their first-ever victory at Sochi, finishing seventh in the Drivers' Championship.
Following Williams backing, Sargeant debuted in Formula 2 in the penultimate 2021 round with HWA Racelab. He then joined Carlin alongside Liam Lawson for the full 2022 season. He scored his first pole and victory at Silverstone, then inherited a second consecutive feature race win at the Red Bull Ring after ahead-of-him disqualifications and penalties. He finished the season fourth in the championship on 148 points with two wins, two pole positions, and four podiums — one point behind Lawson and enough to secure his FIA Superlicence.
Williams announced Sargeant as a 2023 race driver after he completed his superlicence requirements at the 2022 Abu Dhabi Grand Prix weekend. He made his Formula One practice debut at the 2022 United States Grand Prix, becoming the first American in a Grand Prix weekend session since Rossi in 2015. He chose number 2, last used by Stoffel Vandoorne.
In 2023 his debut season was difficult, marked by multiple crashes and qualifying struggles. He was out-qualified by teammate Alex Albon at all 22 races. His sole championship point came at the United States Grand Prix, where he finished 12th and was subsequently promoted to tenth following the disqualifications of Lewis Hamilton and Charles Leclerc — making Sargeant the first American to score a Formula One point since Michael Andretti at the 1993 Italian Grand Prix.
He was retained for 2024. After crashing heavily in Dutch Grand Prix practice and missing qualifying, he was released from the team immediately after the race and replaced by Formula 2 driver Franco Colapinto for the remainder of the season. His best qualifying result of 2024 had been twelfth in Canada and his best race result eleventh at the British Grand Prix.
In 2025 Sargeant stepped back from racing temporarily, citing the emotional and physical toll of his Formula One stint. He returned with an LMP2 seat at PR1/Mathiasen Motorsports for the final two rounds of the 2025 IMSA SportsCar Championship. For 2026 he was confirmed for Era Motorsport in the LMP2 class at the Daytona 24 Hours, and for Proton Competition in the LMGT3 class of the FIA World Endurance Championship. He was also confirmed as one of three Ford factory LMDh drivers for the 2027 FIA World Endurance Championship.
Sargeant's path — from karting world champion to Formula One — traced one of the most complete European junior ladder progressions by any American driver in the modern era. His Williams tenure, though ending in early release, broke a long gap in American Formula One representation and earned him a place in the record books alongside Andretti and Rossi.