Oonagh has served as Secretary General of the Department of Climate, Energy and the Environment since 2023.

During her tenure to date, Oonagh has led the development and delivery of landmark policies to accelerate Ireland’s clean energy transition, including major investment in the electricity grid, the expansion of offshore and onshore renewable energy, and the implementation of ambitious climate action targets. Under her leadership, the Department has played a central role in advancing Ireland’s energy security, decarbonisation, environmental and circular economy ambitions.

Prior to taking up that role Oonagh served as Interim Chair of An Bord Pleanála, on secondment from her role as Deputy Secretary General in the Department of Justice with responsibility for civil justice matters, including immigration, courts and civil and family law. Oonagh had previously held the position of Director General in the Workplace Relations Commission. Before that she worked at a senior level in a number of Government Departments, including the Departments of Public Expenditure and Reform, Environment and Foreign Affairs.