A founding myth of the euro was that profound economic convergence could be achieved across the core and periphery of Europe. Scholarship from within Comparative Political Economy (CPE) has compellingly pointed to this myth of convergence as the fundamental mistake of the euro project (Regan, “Imbalance of Capitalisms”). Economic and Monetary Union was applied across a range of incompatible varieties of capitalism with little appreciation for how difficult it would be for peripheral economies to overcome long-standing institutional stickiness. Yet, while institutional stickiness tells us much about the causes of declining competitiveness, it tells us much less about the origins of brand new patterns of debt-led growth. This article modifies this CPE account by drawing attention to the much overlooked case of Portugal. In contrast to CPE’s emphasis on institutional stickiness, this paper explores the ways in which negotiation of European integration has been generative of institutional transformation leading to debt-led growth in Portugal. By combining Europeanisation with CPE, this article shows that, far from an inability to do so, in the case of Portugal, it has been the attempt to ‘follow the rules’ of European Integration that explains its damaging patterns of debt-led growth.