Jack Hess who has a master degree in education
and who taught six years at boarding schools, is the new Dean of Discipline at Harbor High and is responsible for the measures to be taken after the gunshot incident. He wishes to punish Marissa Cooper but is only able to expel her. When Ryan Atwood punches him in the face, Jack uses that to have expelled Ryan as well. He is also responsible for Summer Roberts losing the social chair to Taylor Townsend by tricking her to admit that she stole a theatrical set. At the Summer Dance, Summer sees Taylor and Jack sharing an intimate tryst and Sandy uses the information to blackmail Jack into leaving Harbor to save his career.
Played by Eric Mabius.