Thierry Dallard is a normalien (1987), holder of a doctorate in fluid mechanics at the University of Paris VI - Pierre and Marie Curie (1991) and graduate of the National School of Ponts et Chaussées (1993).

He began his career (1992-1993) as a consultant on large rail line projects speed in Italy before joining the Ministry of Transport in 1994 as director of infrastructure and transport in Aix en Provence. In 1999, he became head of the travel and transport infrastructure department within the departmental equipment directorate of Bouches-du-Rhône. In 2003, he was appointed director development within the Autoroutes du Sud de la France (ASF), then in 2004 was responsible for implementation of decentralization and reform of the DDEs, then the creation of new project management services, within the General Directorate of Roads. In 2007, he joined Meridiam, a French investment fund specializing in the development and private financing of public infrastructure, in charge of the French market. Since June 2018, he has served as Chairman of Société du Grand Paris.