Sibley joined Derby County's academy in 2010, making his first-team debut in December 2019, after he was a part of the club's U18 Premier League championship in 2018–19.
Sibley played in over 170 first-team matches for Derby and, during the 2023–24 season, helped the club win back promotion the Championship after a two-year absence in League One.
[7] On 28 August of the same year, Sibley received his first senior start, again in the EFL Cup, against Nottingham Forest, which ended in a 3–0 loss.
[14] Sibley stayed at Derby, however, and scored the winning goal in stoppage time in a 1–0 success over Peterborough United on 19 February 2022.
Sibley was unable to take part in any of the pre-season fixtures ahead of the 2023–24 season or the opening five league matches because of a calf injury.
[19] Sibley's first three goals of the season came in the EFL Trophy, once against Lincoln City on 19 September 2023[20] and twice in a 2–1 win at Notts County on 10 October 2023.
[citation needed] On 6 September 2021, Sibley made his debut for the England U20s during a 6–1 victory over Romania U20s at St. George's Park.