Alfie Gilchrist was born on 28 November 2003 in Kingston upon Thames, London, and began his football journey at local side Old Isleworthians Youth F.C. and Queens Park Rangers before joining Chelsea's academy at under-11 level in 2014. A boyhood Chelsea supporter whose grandfather and father were season ticket holders, he grew up idolising John Terry and gradually developed into a right-back during his time in west London.
Gilchrist rose steadily through Chelsea's youth ranks, captaining the academy side to the FA Youth Cup semi-finals and winning the Under-18 Premier League Cup in 2021–22. He made his senior debut in December 2023 as a substitute in a 2–1 Premier League win over Crystal Palace, and scored his first Chelsea goal in April 2024 — coming off the bench to net in a 6–0 victory against Everton.
A composed, right-footed defender who is equally comfortable defending one-on-one and contributing in transition, Gilchrist spent the 2024–25 season on loan at Sheffield United, making 30 Championship appearances and helping the club keep 15 clean sheets as they finished third and reached the play-off final.
In August 2025, Gilchrist made a permanent move to West Bromwich Albion on a four-year deal. West Brom have taken him on as a key part of their defensive setup in the EFL Championship, and he marked his debut for the club with an appearance as a substitute in a 1–0 win at Norwich City in October 2025.