Microfinance is used to enhance micro and small enterprise start-up and growth in developing countries. Although there is some discussion of how microfinance institutional activities lead to their own sustainability in the extant literature, the same cannot be said of the ways in which microfinance institutions shape the sustainability agendas of micro and small enterprises (MSEs). In this paper, we conceptualise and explain the way that joint liability lending in microfinance shapes the sustainability of micro and small enterprises owned by borrowers. Using sustainable leadership as a theoretical foundation, we conceptualise the strategic, operational, and community-level leadership functions associated with joint liability and construct a framework. Based on the conceptual framework, we also develop propositions and explain them using an illustrative case study. Our conceptual work reveals that leadership tasks at strategic, operational, and community levels influence MSEs’ sustainability. Our conceptual framework, propositions, and illustrative case evidence contribute to theory and practice by highlighting that joint liability mechanisms are a possible pathway for MFIs to facilitate sustainable initiatives in micro and small enterprises.