This study aims to understand the dynamics of shared leadership in the context of intrapreneurship, in particular its connections with the effectiveness of groups in carrying out innovative projects. The study examines these dynamics within an organization that has a traditional and hierarchical organizational structure in the state banking sector, analyzing the case of ideiaLab/BNDES, a strategy adopted by the company to foster innovation through employee engagement. The research, of a qualitative nature, was based on documentary data provided by the institution and on data collection through interviews conducted with participants from 10 work groups involved in ideiaLab, totaling 16 interviews. The data were analyzed by applying the Ground Theory protocol. As a result, the research presents an explanatory model for the dynamics of leadership in voluntary intrapreneurship based on the case of ideiaLab, highlighting the nature of the initial entrepreneurial motivation, the formation of groups, the asymmetry of the competences of the members and their impact on the dynamics of leadership sharing. The findings also highlight the role of expanding the limits of influence (boundary spaming) in intrapreneurship, a factor that seems to favor the effectiveness of teams in achieving results.