Abstract
The challenges introduced by sustainable development deeply affect purchasing and supply management practices and therefore foster a change in the firm's supply network. After a literature review on supply network management, sustainable sourcing and legitimacy, this paper presents the results of an in-depth case study of a gardening distributor which adopted a sustainable strategy. The analysis illustrates how the firm conquers its legitimacy in sustainable development through the evolution of its supply network. The paper highlights three types of legitimacy – product legitimacy, corporate legitimacy and cause legitimacy – and reveals the different roles of business and non-business actors in the firm's extended sustainable supply network.