Examining core executive organization for EU affairs in Finland and Sweden, this article uncovers how change agents used European integration deliberately to strengthen their role in the domestic settings through taking control of EU policy co-ordination. In both countries, EU membership was an exogenous factor that enabled the offices of the PM to secure a more powerful position and advance their own institutional agendas. This strengthened their leadership role and weakened the respective foreign ministries, whose legitimacy in EU co-ordination was undermined by the discourse that matters pertaining to this co-ordination should be treated as domestic policy instead of foreign policy. This discourse proved instrumental in the organizational reforms and core executive restructuring. Both countries also provide evidence of intra-Nordic organizational learning since the Finnish co-ordination system was based on lessons drawn from Denmark whereas the subsequent Swedish reform was inspired and legitimized by changes in Finland.