The proliferation of sustainability standards by multi-stakeholder initiatives that create and promote them has been studied as an organizational field for sustainability (Dingwerth and Pattberg 2009). The aim of this article is to gain a better understanding of the institutionalization process of this global organizational field by focusing on the case of the ISEAL Alliance (the global association for sustainability standards). We show that specific strategies have been put into place by ISEAL so to expand the role and influence of sustainability standards. This institutional entrepreneurship consists primarily of two dimensions: institutionalizing an organizational field based on a market-driven procedural vision of sustainability and simultaneously legitimating both the tools and ISEAL as the means to achieve sustainability through external enrollments, entanglements and alliances. The characterization of ISEAL’s activities in this way extends our understanding of how the micro-dynamics within organizational fields are interdependent upon macro-dynamics outside organizational fields.