On 20 December 2023, he resigned as Health Minister in response to the passage of a controversial immigration bill backed by his government.
[4] From 2015 to 2017, Rousseau served as deputy director of the cabinet and advisor on social affairs to successive Prime Ministers Manuel Valls and Bernard Cazeneuve.
[6][7] Rousseau won plaudits for running the public health authority in the Paris region during the COVID-19 pandemic in France.
[8] In October 2023, Rousseau participated in the first joint cabinet retreat of the German and French governments in Hamburg, chaired by Chancellor Olaf Scholz and President Emmanuel Macron.
[9][10] In the 2024 French legislative election, he stood under the label of Place Publique as a candidate of the New Popular Front in Yvelines's 7th constituency, winning the seat from Renaissance's Nadia Hai.