Over a more than 35-year career Professor Ian Cartwright's research has provided advances in the understanding of a wide range of earth-science processes, from metamorphic geology to palaeo-climates, groundwater hydrology, catchment hydrology and geochemistry. His research has predominantly utilised geochemistry, stable and radioactive isotope tracers to understand links between palaeo-climate and groundwater, geochemical processes impacting on groundwater and surface water quality, and metamorphic processes. He has made outstanding contributions to scientific knowledge and training through mentoring numerous PhD and masters students, journal editorial roles – including as a long-time Associate Editor for Applied Geochemistry, and active participation in conferences, professional societies and working groups – such as the Applied Isotope Geochemistry group and the International Association of Geochemistry. As he moves into retirement, we take the opportunity to summarise his impact and contributions across many scientific disciplines and reflect on the significance of his distinguished career.