After his military service in the Artillerie de Montagne, he was put in charge of a mission for the Economy Ministry, during the government of the Front populaire.

In 1961, he investigated and denounced Maurice Papon, the prefect of the police force, in connection with the shootings of Algerian FLN demonstrators on 17 October of that year, in the Paris massacre of 1961.

Bourdet's political militancy created tensions which led to a major rupture of the France-Observateur team in 1963, and his subsequent departure from the newspaper.

He continued to publish articles in Témoignage chrétien, Politique Hebdo or Politis, and took part in the special numbers of the Nouvel Observateur.

In 1985, Bourdet was a member of the "Jury of Honor" that assessed whatever the film Des terroristes à la retraite should be aired in France or not.