Smallholder farmer-based rural social movements have been heralded as a promising source of political power with the potential to effectively promote sustainable trajectories of agricultural development in Sub-Saharan Africa and beyond. However, the very early stages of rural social movement building remain understudied, including under what conditions such nascent efforts are likely to lead to effective political influence and foundations for broader collective action. Drawing on insights from organizational studies and resource mobilization theories, we provide an analytical narrative of the emergence and development of a smallholder farmerbased policy advocacy organization, the Peasant Farmers Association of Ghana (PFAG). Through analysis of organizational documents and an extensive open-ended focus group interview with PFAG's founders, long-term members, and current staff, we discuss how PFAG managed to overcome the "liability of newness" faced by new organizations, and how its resulting organizational structure influences its modes of resource mobilization and thus type and coverage of its advocacy and service delivery activities. Considering this developmental narrative, we elaborate several challenges that PFAG faces in pursuit of its ambitions to expand its influence in Ghanaian agricultural policy and practice. Our findings indicate the need for PFAG to address emerging contradictions in project activities and uneven geographical coverage, manage tensions between advocacy and service delivery objectives and to work towards establishing an umbrella agenda capable of providing for the diverse and evolving needs of their membership base.