In January 2020, Campbell moved to Iceland, joining the Fimleikafélag Hafnarfjarðar youth team. The following day, he joined
Breiðablik on a short-term deal, effective until his move to Dortmund in July. He left Iceland in June 2022, following one appearance with Breiðablik. In January 2024, Campbell was one of several Dortmund youth players who joined the senior team's winter training camp before the second half of the
2023–24 season in
Marbella, south Spain. At the camp however, the club disciplined Campbell and
Paris Brunner for leaving the team hotel after their midnight curfew. On October 26, 2024, Campbell made his professional debut for Borussia Dortmund, coming on as a substitute for
Donyell Malen in a 2–1 loss to
FC Augsburg. On January 5, 2026, Campbell was loaned by
TSG Hoffenheim in
Bundesliga until the end of the 2025–26 season, with an option to buy. ==International career==