The ‘free enterprise’ system is a normative cornerstone of many Latin American political constitutions and a formative principle of neoliberal legality. However, the way in which this economic model shapes the legal field and conceptions of the rule of law remains understudied. Though lawyers, judges, and legal experts have played an important role in the legal buttressing of the free enterprise model, this article explores the shaping of neoliberal legality from the periphery of the juridical system. We argue that the rise of neoliberal legality in Latin America owes much to the legal imaginary crafted by business associations. In line with this, we examine the ‘norm entrepreneurship’ undertaken since the 1940s by an organization barely noted in mainstream histories of neoliberalism: the Inter-American Council for Commerce and Production (IACCP). Drawing on the concept of social constitutionalism and archival work, we investigate the IACCP's role in the struggle to give business activities social legitimacy and establish free enterprise as a socio-legal norm and a source of public law.