Jean Castex graduated from France’s École Nationale d’Administration (ENA) in 1991 and began his career at the Court of Auditors, becoming a Senior Advisor in 2008. Over the years, he held several key administrative positions, including Director of Health and Social Affairs in the Var department (1996); Secretary General of the Vaucluse Prefecture (1999–2001); and President of the Alsace Regional Chamber of Accounts (2001–2005).

From 2011 to 2012, he served as Deputy Chief of Staff to the President of France.

In 2008 he was elected mayor of Prades, a town in the Pyrénées-Orientales department, and held that office until 2020. He also served as a regional councillor for Languedoc-Roussillon from 2010 to 2015 and a departmental councillor for the Pyrénées-Orientales from 2015 to 2020.

In 2017, he was appointed to oversee preparations for the 2024 Olympic and Paralympic Games in Paris. In 2020, President Emmanuel Macron named him Prime Minister of France, a role he held until 2022, during which he managed the government’s response to the Covid-19 pandemic and the gradual lifting of national lockdown measures.

Before he was appointed as Chief Executive Officer of the SNCF Group on 23 October 2025, Mr Castex served as Chairman and CEO of RATP starting in 2022.