A search of the Irish State Administration Database (ISAD, www.isad.ie), which records the origins, life cycle, policy domain and functions of all central public organisations since the foundation of the Irish state over a century ago, reveals that, following the formative and turbulent year of 1922, the Office of the Comptroller and Auditor General was the first new agency formally established in 1923. The primacy given to what we might now refer to as a supreme audit institution (SAI) for the public sector reflects the importance of financial control to the effective functioning and legitimacy of the executive organs of the nascent state. In this paper we analyse the changing range and scope of functions undertaken by the Comptroller and Auditor General in its first century. We examine first the sustained growth in the number and type of public bodies subject to Comptroller and Auditor General scrutiny. Second, we look at the broadening in scope of audit functions beyond the traditional concerns of regularity, ensuring the money was spent for the purposes for which it was given (financial and compliance audit), to encompass wider values such as efficiency, economy and effectiveness and even performance, more broadly conceived. Finally, as well as the instrumental perspective on the role of the Comptroller and Auditor General’s Office, we reflect on the key relationships and cultural and symbolic dimensions of the Office’s work across time. From this analysis we draw some conclusions about the nature of financial control in the contemporary state, as compared with the early Irish state.