Young-Coombes is a product of the Crystal Palace, Chelsea and Rangers academies and he began his professional career with Brentford in 2021.
[10] On 9 June 2021, Young-Coombes signed a three-year contract, with an option of a further year, with the B team at newly-promoted Premier League club Brentford.
[9] Prolific goalscoring for the B team saw Young-Coombes called into the first team squad during the 2021–22 season and he remained an unused substitute during eight matches,[11][12] before finally making his senior debut as a late substitute for Mathias Jensen after 87 minutes of a 3–0 Premier League win over Southampton on 7 May 2022.
[21] He made two appearances during the latter stages of the team's 2022–23 Premier League Cup campaign and scored in the 2–0 Final victory over Blackburn Rovers.
[23] An ankle injury saw Young-Coombes miss nearly four mid-season months and he failed to win a call into a first team matchday squad during the 2023–24 season.