The aim of this paper is to provide clues to industry and academia on how best to approach the challenge of developing a sustainable supply chain. A case study was undertaken of the Westpac Banking Corporation – one of the world's most socially responsible banks – to examine how they approached the challenge of managing corporate social responsibility (CSR) in their supply chain. This paper highlights some of the challenges and opportunities associated with extending corporate governance beyond the firm boundary. Specific attention is given to a discussion of assessment and governance tools. The use of a single case study limits the generalizability of these findings. Future research can build on these findings by extending the scope to include additional firms, regions and methods. A best practice model is developed from the discussion to provide practical guidance to firms. While the extension of CSR to the supply chain is an emerging area of interest, the literature provides few clues on how best to pursue sustainable supply chain management. This paper provides a valuable and timely contribution to this topic by reviewing the lessons and practices of a recognised CSR leader.