Zhou took up karting at the age of eight in China before relocating to Sheffield, England in 2012 to pursue a more competitive racing environment, where he attended Westbourne School. In 2013 he raced with the Sheffield-based Strawberry Racing team, winning both the Super 1 National Rotax Max Junior Championship and the Rotax Max Euro Challenge. He competed alongside future Formula One drivers Lando Norris and Jehan Daruvala at the Karting World Championship, driving for Ricky Flynn Motorsport.
Zhou joined Prema Powerteam for the 2015 Italian F4 Championship, sweeping all three races in Round 2 at Monza and finishing the season as vice-champion and best rookie. He followed this with three seasons in the FIA Formula 3 European Championship, starting with Motopark in 2016, then rejoining Prema for 2017 and 2018. His final F3 campaign yielded two wins, three pole positions, and an eighth-place championship finish. During these years he was a member of the Ferrari Driver Academy from 2014 to 2018.
In 2019 Zhou left Ferrari's programme and joined the Alpine (then Renault) Academy, entering the FIA Formula 2 Championship with UNI-Virtuosi alongside Luca Ghiotto. He took a feature race podium on debut in Barcelona, became the first Chinese driver to claim a Formula 2 pole position at Silverstone, and finished seventh in the championship as the highest-placed rookie, earning the Anthoine Hubert Award. He remained with Virtuosi for 2020 and 2021; in his third F2 season he claimed four victories and nine podiums, ultimately finishing third in the championship behind Oscar Piastri and Robert Shwartzman. He also claimed the 2021 F3 Asian Championship title with four wins and eleven podiums for Abu Dhabi Racing by Prema.
Alongside his F2 career, Zhou served as a development and test driver for Renault in 2020 and Alpine in 2021, making his Formula One race weekend debut during the first practice session of the 2021 Austrian Grand Prix.
Zhou signed a three-year deal with Alfa Romeo for 2022 alongside Valtteri Bottas, choosing race number 24 as a tribute to basketball icon Kobe Bryant. He scored a point on debut at the Bahrain Grand Prix after starting fifteenth and recovering from a poor start. At the 2022 British Grand Prix he was involved in a high-speed opening-lap collision with George Russell that sent his car airborne, flipping it upside-down over the barriers into the catch fence. He was extracted unharmed and later credited the halo device with saving his life. He ended the season eighteenth in the Drivers' Championship with six points, compared to Bottas's 49.
The 2023 season produced a similarly modest haul. Zhou scored points in Australia, Spain, and Qatar, again finishing eighteenth with six points. His best qualifying result came at the Hungarian Grand Prix where he reached fifth in Q2, though a first-corner collision and subsequent time penalty undid that promise.
Following the expiry of Alfa Romeo's title sponsorship, the team rebranded as Stake F1 Team Kick Sauber. Zhou's sole points finish of 2024 came at the Qatar Grand Prix, where he qualified twelfth and climbed to eighth after two safety car interventions, being voted Driver of the Day. He also set two fastest laps across his Formula One career. Zhou departed Sauber at the season's end as Nico Hülkenberg and Gabriel Bortoleto were signed for the team's transition to Audi ownership.
Zhou joined Ferrari as a reserve driver for 2025 but was not retained for 2026. In January 2026, he was announced as a reserve driver for Cadillac's first Formula One season, continuing to remain on the fringes of the grid.
Zhou Guanyu's arrival in Formula One in 2022 represented a landmark moment for Chinese motorsport, making him the first driver from mainland China to participate in a full World Championship season. Despite operating with machinery that rarely allowed top-ten finishes, he established himself as a consistent and professional competitor across three seasons, accumulating sixteen championship points and two fastest laps while withstanding serious physical danger at Silverstone in 2022.