The technical director looks after a whole host of things that offer an element of continuity above and beyond the usual stuff of individual managers. The role tends to include, and this is by no means a comprehensive list: responsibility for and the overseeing of the academy, the training ground, the infrastructure, medical, physiotherapy, conditioning, fitness, nutrition, hydration, rest, well being, and culture and behavioral standards within the club.
The technical director can also have a remit for coaching programs and philosophy (coaching the coaches). It is a role typically found within a nation's football association as well as big and also ambitious smaller clubs. It tends to be a role designed to facilitate long-term strategy and continuity independent of a manager's remit with the team.