The changes observed in the school context demand new practices and impose new challenges to the operational assistants that, due to their relevant role in the educational environment, must be prepared and endowed with knowledge and skills to conduct their profession in a fully useful way. This is only possible through the promotion of their training and capacitation in a real work context. Through the European project entitled “Innovative Plans to Combat School Failure” which was implemented in Portugal, we assess the impacts of a training-capacitation action directed to operational assistants and explore the dynamics and influences underlying the learning process put in practice in the schools of the county of Sintra. This assessment conducted by a higher education institution (Iscte-University Institute of Lisbon) mobilized a mixed methodology-survey and focus groups with operational assistants and interviews conducted to school directors. We verified that a training activity conducted in the real working context potentiates the performance of these professionals, namely in terms of autonomy and adaptation to different contexts and duties, conflict management and cooperation, whose effects reflected on the organizational dynamics of the school institutions of the county of Sintra.