He was the son of Protestant religious leader Edmond de Pressensé.
After a short period at the Ministry of Public Instruction, he entered the diplomatic service, and was appointed first secretary at Washington, D.C.
He was a contributor to many journals, including the Revue des Deux Mondes and the République Française, and in 1888 became foreign editor of the Temps.
He wrote in support of General Picquart, and in consequence of his advocacy of Émile Zola's cause was struck off the roll of the Legion of Honour.
He was prominent in the debates on the question of the separation of church and state, and a bill brought in by him formed the basis of the one finally carried by Aristide Briand.