Mission-oriented Innovation Systems (MIS) play a crucial role in policies for sustainability transitions, yet their development through bottom-up dynamics is not well understood. We mobilized innovation functions and Resources-Based-View approaches to investigate how a formal network in the agri-food sector developed as an MIS. Within the conceptual framework we built, innovation functions are entry points for understanding how collective action leads to resource sharing and building. This study investigates the FILEG association in southern France, created to promote the sustainable development of the regional legume value chain, involving over 70 actors. Data collected through desk research, a questionnaire, and interviews reveal diverse perceptions among members regarding the association's contributions to innovation functions. This raises questions about the collective's ability to achieve internal and external legitimacy and highlights the need for dialogue between MIS and institutional approaches, which could advance governance and coordination as a key innovation function in MIS.