Poirot-Delpech came from a family of academics and doctors. His ancestors included several surgeons. His father died in 1940.

He attended Stanislas and Louis-le-Grand secondary schools, completing his khâgne at the latter.

At the age of 22, he began his career as a journalist with Le Monde. He successively had charge of several sections: the university column (1951—1955), the "Great Trials" column (1956—1959) and the theatre criticism section (1960—1971). In 1972, he took over as a reviewer for the "Monde des Livres". Beginning in 1989, he wrote a weekly column in Le Monde.

Bertrand Poirot-Delpech chaired the Syndicat de la Critique Dramatique (1970—1972) and he was a member of the reading committee of the Comédie-Française.

In addition to several published novels, he wrote screenplays for television and the cinema.