*Club domestic league appearances and goals, correct as of 20:02, 28 October 2024 (UTC) ‡ National team caps and goals, correct as of 20:53, 24 March 2024 (UTC)
Born in Kingston upon Thames, where he lived only 15 minutes away from the Cobham Training Centre, Castledine started his career with Chelsea, who he had supported growing up.[3] He spent two years with Chelsea before moving to AFC Wimbledon at the age of seven.[3] Growing up, he also played rugby, and was enrolled in the elite academy of professional club Harlequins.[3]
Initially beginning his career with Wimbledon in a more defensive role, he moved up the pitch to operate as a midfielder.[4] Settling into his new role well, he was involved in Wimbledon under-18's pre-season tour of Italy, playing alongside players four years his senior, and went on to make his under-18 debut in 2019 - becoming the youngest Wimbledon player to ever do so.[4]
A year later, in March 2020, he rejoined Chelsea, naming Mason Mount and Jack Grealish as his favourite current players.[4][5] He signed his first professional contract with The Blues in August 2022, on his seventeenth birthday, and has already been called up to train with the first team.[3][6]
Castledine made his senior debut for Chelsea as a substitute in a 6–1 EFL Cup semi-final second-leg win over Middlesbrough on 23 January 2024.[7]
