The ex-Canada international has been promoted to Aron Winter's team after spending the past three seasons as head coach of the club's youth academy.
"(Bent) has proved he is ready to take the step up," Winter said in a statement.
"Developing our young players is a key part of our philosophy at this club, and having Jason working with the first-team squad will help us with that. It is also the next step in his development as a coach and we believe he has a bright future ahead of him."
Bent's playing career was cut short in 2004 by a knee injury after eight seasons at the top professionally.