Zhou began karting at the age of eight in China. In 2012 he relocated to Sheffield, England, attending Westbourne School to access a more competitive international racing environment. His 2013 karting season with the Sheffield-based Strawberry Racing team produced victories in both the Super 1 National Rotax Max Junior Championship and the Rotax Max Euro Challenge. During his final karting year Zhou finished runner-up in the Rotax Max Senior Euro Challenge and made an appearance in the Karting World Championship driving for Ricky Flynn Motorsport alongside Lando Norris and Jehan Daruvala.
Zhou joined Prema Powerteam for the 2015 Italian F4 Championship. A dominant weekend at Monza, where he won all three races in Round 2, set the tone for a season in which he consistently challenged for the podium. He finished as vice-champion and best rookie. He also competed in selected rounds of the German ADAC F4 Championship, taking two podium finishes at Spielberg and Spa.
Zhou spent three seasons in the FIA Formula 3 European Championship. His 2016 debut with Motopark ended in 13th place after a strong opening — two podiums in Paul Ricard and the Hungaroring — followed by a difficult second half. He returned to Prema for 2017 and improved to eighth, accumulating five podium finishes that included holding off Lando Norris in the penultimate round at Spa.
For 2018 Zhou stayed with Prema for a third F3 campaign. He took his maiden F3 victory in Pau and added a second win at Hockenheim, but four consecutive retirements due to collisions and tyre punctures in the second half of the year prevented a title challenge. He finished eighth, with three poles and two race wins.
Zhou joined UNI-Virtuosi Racing for the 2019 FIA Formula 2 Championship, partnering Luca Ghiotto. He collected his first Formula 2 podium at Barcelona and a third place at Monaco, then secured the first Formula 2 pole position by a Chinese driver at Silverstone. He was awarded the Anthoine Hubert Award as the highest-finishing rookie, placing seventh in the championship.
In 2020, remaining at UNI-Virtuosi alongside Callum Ilott, Zhou won his first Formula 2 race in Sochi and added five further podiums across the season, finishing sixth in the championship despite an electronic failure while leading in Austria.
His 2021 campaign produced the strongest Formula 2 performances of his junior career. Starting at Bahrain, he converted pole position into a feature race victory, and added further wins in Monaco, Britain, and Abu Dhabi. Despite losing ground to Oscar Piastri mid-season through a spin in Azerbaijan and a stall in Sochi, Zhou recovered to finish third in the championship with four wins and nine podiums. Over the winter he also won the 2021 F3 Asian Championship with Abu Dhabi Racing by Prema, taking four wins and five poles.
Zhou was a member of the Ferrari Driver Academy from 2014 to 2018, before joining the Renault — later Alpine — Driver Academy from 2019 to 2021. He served as a development driver for Renault F1 in 2019 and was promoted to test driver in 2020, participating in three post-season test sessions including at Yas Marina Circuit alongside Fernando Alonso.
Zhou signed a multi-year contract with Alfa Romeo for 2022, partnering Valtteri Bottas. He chose race number 24 in tribute to his sporting hero, basketball player Kobe Bryant. On his debut at the Bahrain Grand Prix he qualified fifteenth and finished tenth to score a championship point, becoming the first driver from mainland China to do so.
At the British Grand Prix, Zhou was involved in a major first-lap accident in which his car flipped upside down and slid across the gravel before becoming lodged in the catch fencing. He was extracted and declared fit, later attributing his survival to the halo. The season's most productive result came at the Canadian Grand Prix, where he reached Q3 for the first time and finished eighth. He closed the season eighteenth in the championship with six points.
Zhou remained at Alfa Romeo for 2023. His points finishes came at the Australian Grand Prix (ninth from seventeenth on the grid), the Spanish Grand Prix (ninth from thirteenth), and the Qatar Grand Prix, where he advanced from last on the grid to ninth after benefitting from retirements and extreme-heat attrition. He qualified fifth at the Hungarian Grand Prix — his best Formula One qualifying result — but was given a time penalty following a first-corner collision. He finished eighteenth in the championship with six points, an identical tally to 2022.
Zhou continued with the team into 2024 as it transitioned from Alfa Romeo branding to Stake F1 Team Kick Sauber. The season was difficult, but Zhou delivered the team's only points finish with the C44 at the Qatar Grand Prix, qualifying twelfth and finishing eighth after two safety car periods; he was voted Driver of the Day. He accumulated two fastest laps and sixteen championship points across his Formula One career before leaving Sauber at the end of the season, replaced by Nico Hülkenberg and Gabriel Bortoleto.
Zhou joined Ferrari as a reserve driver for the 2025 season. In January 2026 he was announced as a reserve driver for Cadillac's inaugural Formula One campaign.
Zhou Guanyu's arrival in Formula One marked a milestone for Chinese motorsport, opening the door for a market that had long been courted by the sport's commercial stakeholders. His measured performances across three seasons — often extracting more from the Alfa Romeo and Sauber machinery than the car's pace suggested — earned respect within the paddock, while his survival at Silverstone in 2022 became one of the most discussed safety demonstrations of the halo device in the sport's history.