Prior research has documented the importance of the state and social movements for the emergence and proliferation of alternative organizational forms. Yet, we lack a comprehensive and interactive understanding of the larger environment that sustains cooperatives and other collectivist-democratic organizations. Using the example of Brazil’s Solidarity Economy Movement, a longstanding social movement to address poverty and inequality, we describe how a multilevel ecosystem of organizations and institutions creates conditions favorable for the growth of alternative organizational forms – in this context, democratic cooperatives that the Movement calls solidarity economy enterprises (SEEs). Drawing from archival data, interviews, and a government survey of over 19,000 SEEs between 2005 and 2012, we map out the key actors at each level of the ecosystem, identifying three primary mechanisms by which these actors collectively enabled the creation and development of SEEs: (1) providing glue for action; (2) organizing for action; and (3) engaging in action. These mechanisms, in turn, allowed for greater communication and cohesion and the exchange of information and experiences among the Movement’s participants, thereby enhancing their interconnectedness and the institutionalization of their practices.