Jean Daillant is an experimental physicist (soft-condensed matter). After graduating in Physics at the École Normale Supérieure de St-Cloud, he obtained his PhD from Paris-Sud University in 1989. Author of 120 peer-reviewed publications, his expertise focuses on soft matter physics and liquid interfaces, delving into their intermolecular interactions and surface phenomena. Utilising advanced techniques like synchrotron X-ray and atomic force microscopy, he has analysed these systems at the nanoscale. His interest also extends to practical applications, particularly in nanomaterials synthesis through self-assembly. In 1989, Jean Daillant joined the CEA, where he subsequently became Head of the Soft Matter and Interfaces Group before becoming joint director of LURE, the French national synchrotron light source in Orsay, from 1999 to 2003. In 2004, he became Head of the CEA-CNRS Laboratory LIONS for Interdisciplinary Research on Nanometric and Supramolecular Organisation. In 2011 and until 2024, he was Director General of the SOLEIL synchrotron. On 1st September 2024, he joined the ESRF as Director General. Widely recognised as an expert on synchrotron radiation, he has been a member of several international committees. After serving as Chair in 2023, he is now Vice-Chair of LEAPs, the League of European Accelerator-based Photon Sources. He also held in 2023 the role of Spokesperson of the Analytical Research Infrastructures in Europe (ARIE).