ABSTRACT Domestic political factors are often overlooked in discussions about the determinants of currency internationalisation. By studying the re-internationalisation of the Yen, our research found that the dynamic interactive mechanism between policy actors has a profound impact on the overall course of domestic currency internationalisation. In the case study, along with the establishment of the “Prime Minister-controlled” model, the “bureaucrat-controlled” policy process of Yen re-internationalisation led by the Ministry of Finance (MOF) experienced substantial intervention by the Prime Minister and related influences. The case study shows that Koizumi exerted pressure on the MOF and the Bank of Japan (BOJ) via budgeting power and the flexible use of resources. Moreover, the MOF and the BOJ relied on accumulated professional financial experience and the resources of legally binding independence in financial policy to successfully safeguard organisational interests and core policy concepts. Our research shows that resource exchange between the three entities helped the Prime Minister to minimise policy confrontation effectively while objectively promoting the interdependence of fiscal, monetary and financial policies, which drove sharp change in the Yen re-internationalisation policy and its long-term outlook. This case study of Japan suggests ongoing concern about the increasing politicisation of the distinctly professionalised currency internationalisation policy.