Earthy joined West Ham United at under-6 level,[4] later signing his first professional contract with the club at the age of 17 in June 2022.

[5] Earthy was part of the West Ham under-18 side that won an FA Youth Cup and U18 Premier League South double during the 2022–23 season.

On 14 March 2024, Earthy made his first team debut for West Ham, coming on as a late substitute in a 5–0 win against Freiburg in the UEFA Europa League round of 16.

[6] On 14 April 2024, Earthy later made his Premier League debut in a game against Fulham coming on as an 82nd minute substitute for Michail Antonio.

Coming on as a late substitute, two minutes later he played a key role in the winning goal as City beat Millwall 4–3.