Max Alleyne was born on 21 July 2005 in Bristol, England, and began his youth career at Southampton, making his under-18 debut during the 2020–21 season at just 15 years old. His performances attracted the attention of Manchester City, who signed him in 2021 for a reported £1.5 million fee, with a sell-on clause also included in the deal. He signed his first professional contract with City in July 2022.
A composed, ball-playing centre-back, Alleyne spent the first half of the 2025–26 season on loan at Championship side Watford before being recalled to City in January 2026 to cover for the long-term injuries to Rúben Dias and Joško Gvardiol. He made his senior debut on 7 January 2026, putting in a steady performance in a 1–1 draw against Brighton & Hove Albion. Days later, he scored his first goal for the club in a 10–1 FA Cup third-round win over Exeter City.
Among his honours, Alleyne was part of the Manchester City squad that won the EFL Cup in 2025–26 and was also listed in the squad that claimed the FIFA Club World Cup in 2023. He was named Manchester City U21 Player of the Year in May 2025 despite suffering an injury on international duty.
At international level, Alleyne has represented England at various youth levels, earning his England under-20 debut in September 2024 and his under-21 debut in October 2025. He is also eligible to represent Barbados. Manchester City continue to view him as a developing option within their first-team defensive setup.