Despite the diffusion of the paradigm of central bank independence, there is still meaningful variation in the operating missions of central banks both across countries and over time. Through a detailed qualitative case study, this article develops the concept of the operating mission of the central bank and applies it to the case of the Hungarian National Bank (MNB) to provide a more complete understanding of mission shift. Our findings demonstrate the critical role of policy agency, as the central bank governors moulded the operating mission of the central bank, even in the face of dominant international norms.