This chapter reports the results of a multifaceted and longitudinal research project entitled Enabling Sustainability through Action Research (EStAR). Conducted in two phases, with two separate cohorts of small, medium and micro enterprises (SMEs) in southern South Africa, the research project considered how an action research methodology could support the embedding of sustainable business practices and responsible leadership, first, into a diverse group of unrelated SMEs, and, second, into another group of SMEs working independently within a corporate supply chain. The leaders of the SMEs in both groups initially had a limited understanding of the concepts of sustainability and responsibility, and they also had restricted budgets. The results of the first phase reported in this chapter confirm the potential of action research to help instil responsible business practices into SMEs. It was apparent that, following the project, the business leaders demonstrated good understanding and mastering of the knowledge and skills that such practices require. In the second phase of the research, the methodology was extended to study whether large corporate supply chain investment could be linked to sustainable practices in a way that added value to both the SMEs and the corporate body. The second group of SMEs were also independent businesses but all of were working within the supply chain of a large insurance company. The business stream was short term insurance, so the SMEs represented a number of panel beaters, solar heating installers and insurers. This stage of the research highlighted the additional complexity involved when the business practices contributing to sustainability and responsibility are defined and shaped within the corporate–SME relationship of supply chain dynamics. This complexity appeared to inhibit the contribution the action research process was able to make to the intended business changes.