The use of serious games in education, whatever the level of students and the subject of study, is full of promise but also strewn with obstacles. Both aspects have been the subject of numerous studies, a number of which underscore the multiple roles teachers have to embrace, each of them representing a more or less difficult challenge. Many factors come into play, including teachers' familiarity with this particular kind of tools. The research work presented in this article includes both game designers and university teachers in the field of management. Serious games have been used in classroom during a 6-year experiment. This experiment reveals a set of teacher attitudes that have to be adopted during teaching sessions to make the most of an increased students’ engagement. Teachers are led to adopt roles and positions they are not always familiar with, which can lead to certain difficulties or frustrations. How can we better take these new roles into account? Is it possible to turn them into a strength, and to take them into consideration beforehand, when designing teaching sessions, so as to optimize the use of serious games and get the most benefit from them? Finally, we propose to build a grid of these roles, which describes each of them, its benefits and its limits, and provides guidelines to avoid common pitfalls.