Rochefort's career began in 1868 with the founding of the weekly newspaper La Lanterne, which was speedily suppressed for its outspoken opposition to Napoleon III. He was elected to the Corps Législatif by a Paris constituency in 1869. When the empire fell the following year, he became a member of the emergency government of national defense. His open support of the revolutionary Paris Commune (1871) led to his condemnation under military law.

Transported to the penal colony of New Caledonia in 1873, Rochefort escaped in four months. He returned to France under the amnesty of 1880 in order to conduct a press campaign in L'Intransigeant for the extreme Radicals and Socialists. His dislike of the moderate Republicans led him in 1889 to support the reactionary adventurer General Georges Boulanger (Boulanger, Georges), who had taken a leading role in suppressing the Commune in 1871. After the collapse of Boulangism in 1891, Rochefort once more backed the Socialists; then three years later he allied himself again with the right over the Dreyfus affair, which polarized French opinion by its exposure of injustice and anti-Semitism in the army. During his last years Rochefort wrote for the conservative and nationalistic press.