This study provides a rare and timely observational analysis of Medicane Daniel, one of the most devastating storms in Mediterranean history, integrating both physical and biogeochemical responses of the upper ocean to extreme atmospheric forcing. By combining high-resolution SWOT observations with satellite and reanalysis data, the authors demonstrate how pre-existing ocean conditions—including warm-core eddies, elevated ocean heat content, and a marine heatwave—contributed to storm intensification and shaped the magnitude and persistence of ocean mixing, nutrient supply, and biological productivity responses. The results provide an important benchmark for understanding and modeling compound ocean–atmosphere extremes, which are expected to become more frequent in a warming climate.