Although Koster bears the final responsibility for Young Ajax, both coaches will work together on the basis of equality.

Koster began his coaching career as an assistant at FC Eindhoven in 1985. The next season, he became assistent coach at Willem II, where he took over the head coaching job in 1990. In the years after that, Koster coached respectively Roda JC, Helmond Sport, TOP Oss, Excelsior and RKC Waalwijk. With Excelsior, Adrie Koster promoted to the highest league in 2002. As a football player, Koster played for Roda JC and PSV. Adrie Koster earned three caps for Holland.

Maarten Stekelenburg, the current right hand of Aron Winter with Ajax 2, will go on to coach the Ajax B2-juniors from 1 July. This move fits the ambition of Stekelenburg to have the final responsibility for a team.