Kent began racing in Minimoto before progressing through the FAB-Racing MiniGP50 and MiniGP70 British Championships. After success in the Aprilia Superteens Championship he was selected for the Red Bull MotoGP Academy, racing in the Spanish CEV 125GP series. When the Academy closed he transferred to the Red Bull MotoGP Rookies Cup, finishing runner-up in 2010. Kent also took a wildcard 125cc ride at Silverstone that year, which earned him a late-season Grand Prix debut with the Lambretta team at the Japanese Grand Prix.
Kent entered the world championship with Lambretta in 2010, contesting the final two rounds of the 125cc season. He moved to the Red Bull Ajo Aprilia outfit for 2011 and scored 82 points in his first full season, reaching fourth place on the way to eleventh in the standings.
When the Moto3 class replaced 125cc machinery in 2012, Kent remained with the Red Bull Ajo team, which switched to KTM. His teammate Sandro Cortese claimed the inaugural Moto3 title, while Kent secured fourth overall and recorded his first Grand Prix win at the Japanese Grand Prix at Twin Ring Motegi. A second win followed four rounds later at the season finale in Valencia, where a last-corner overtake on Cortese sealed the result.
Kent returned to Moto2 for 2013 with Tech3 alongside Louis Rossi. He scored points on five occasions, with a best finish of twelfth, before breaking his collarbone in warm-up at the Japanese Grand Prix and missing the remainder of the season.
He dropped back to Moto3 for 2014 with the Ajo Motorsport team on a Husqvarna-branded KTM. For 2015 he joined the Leopard-sponsored Kiefer Racing squad, running Hondas. His championship campaign was dominant from the outset: he took his first win for the team in the second race at Circuit of the Americas and immediately followed up with victories in Argentina and at Jerez, becoming the first British rider to win successive lightweight-class Grands Prix since Barry Sheene in 1971. Further wins came in Catalunya, at the Sachsenring, and at Silverstone in his home event.
Heading into the Valencia finale, Kent led Miguel Oliveira by twenty-four points. Oliveira won the race, but a ninth-place finish from Kent was sufficient to secure the title.
Kent moved to Moto2 with Leopard Racing for 2016, joined once again by Oliveira. He left the team after just three races and spent much of the season without a contract, taking a Moto3 wildcard and occasional injury-replacement rides. He eventually signed with Speed Up Racing in Moto2 for 2018 but was dismissed by the team with five races remaining after disputes over team orders.
Kent transitioned to the British Superbike Championship, initially competing at the 2018 Brands Hatch finale for Halsall Racing on a Suzuki before the team folded. He returned to BSB in 2019 on an MV Agusta and later joined Buildbase Suzuki, continuing with that team into 2022 until a practice crash at Donington Park caused hospitalisation. A crash at Donington was followed by further injury in 2021, when a fall caused a dislocated and broken hip.
For 2023 Kent joined a new BSB team established by his personal sponsor, running a Honda as sole rider. In 2024 he moved to the Mar-Train team with McAMS as title sponsor, winning his first British Superbike race at the final round of the season and resigning for 2025.
Kent was part of the Phil Burgan Race Academy, a programme for developing British motorcycle talent managed under the guidance of James Toseland. In August 2019 he received a four-month suspended prison sentence for carrying a knife during an altercation in March of that year, resulting in his superbike team terminating his contract.
Despite a turbulent career following his world title, Kent's 2015 Moto3 championship stands as a landmark moment for British motorcycle racing. His run of four consecutive wins in the early part of that season, and the clinical championship management at Valencia, mark him as one of the most accomplished British Grand Prix lightweight-class racers in the sport's history.