Born in
Nunnington, Harrison began karting at the age of eight. During his karting career, Harrison won the IAME Winter Cup in the X30 Junior class in both 2020 and 2021, whilst also representing Great Britain the same year in the
Karting Academy Trophy. Harrison stepped up to single-seaters in 2024, joining
Rodin Motorsport for the first two rounds of the
Formula Winter Series. After taking a best result of 21st in race two at
Jerez, Harrison joined
Chris Dittmann Racing for the rest of the year as he made his debut in the
F4 British Championship. Harrison began the season with three top-tens in the first two rounds at
Donington Park and
Brands Hatch, which included a rookie win in the former. After missing the round at
Thruxton, Harrison took two rookie podiums at
Silverstone as he finished sixth and ninth overall in the final two races of the weekend, before matching his season-best result two rounds later at
Knockhill, in which he finished all three races on the rookie podium. After taking one more points finish in the last three rounds, a seventh-place in race one at
Brands Hatch, Harrison ended the year 20th in the overall standings, on 24 points. In late 2024, he also made a one-off appearance in the
Italian F4 Championship for
Jenzer Motorsport at
Monza, taking a best result of 15th in race one. Returning to the Swiss team for 2025, Harrison joined them to race in the
Formula Winter Series,
Italian F4 and
E4 Championships. In the former, Harrison took his maiden single-seater podiums by finishing third in the final two races of the season at
Barcelona on his way to seventh in points, before then making a one-off appearance in the
Formula 4 CEZ Championship at the
Red Bull Ring, winning the first two races and finishing third in race three. In
Italian F4, Harrison started off the season by taking four points finishes in the first two rounds, with a best result of sixth at
Vallelunga, before scoring his maiden series podium in the following round at
Monza by finishing third in race three. Following that, Harrison had to wait until
Misano to score his next and final points of the season, by finishing seventh in race three en route to a 14th-place points finish. During 2025, Harrison stepped up to
GB3, joining
JHR Developments for the final two rounds of the season at
Donington Park and
Monza. On his debut round, Harrison finished second in race three to secure his first and only podium of the season, helping him end his part-time stint 28th in points. The following year, Harrison joined
Double R Racing to race in the Eurocup-3 Spanish Winter Championship and the main series. In the former, Harrison scored a best result of 15th in the
Aragón sprint en route to a 27th-place points finish. ==Karting record==