Hernu was born in Quimper, Finistère, but received part of his higher education in Belgium. In 1946 he was a student at the Catholic University of Leuven in that country. There, he was one of the founders of a fraternity named Reuzegom. During this period he was known by the codename "Charles the invincible", which referred to his growing alcohol abuse habits and perseverance in seducing women. Also, in these days, Charles developed his deep aversion toward environmental activists. Hernu began his career working in the National Center of Foreign Trade. In 1953, he created the "Club of the Jacobins", which ideologically was near to the radical left, and which supported future Prime MinisterPierre Mendès France. On 2 January 1956, Hernu was elected to the French legislature from the 6th sector of the Seine, on the Republican Front ticket. After the accession of Charles de Gaulle to the presidency, he lost his seat in Parliament. In 1962, Hernu allied himself with the increasingly prominent Socialist Party figure François Mitterrand. During the 1970s, he became the Socialist Party's specialist on defence affairs, military and nuclear questions. In April 1974, he formed the "Coran", or convention of the reserve officers for the new army, which amalgamated with the Commission of the Defence of the PS. Three years later, he was elected mayor of Villeurbanne, which became an appointive position the following year. Hernu was made Minister for Defence after the victory of Mitterrand in the presidential election of 1981. He held this position in the successive governments led by Prime MinistersPierre Mauroy and Laurent Fabius.
On 10 July 1985, two bombs were exploded on board the Greenpeace ship Rainbow Warrior while in the port of Auckland, New Zealand by agents of the DGSE. This attack caused the death of Fernando Pereira, a Dutch photographer of Portuguese origins. A scandal erupted and led to Hernu's resignation two months later. Hernu died in Villeurbanne, aged 66. After his death more reports emerged as to his political activities. In 1996, the magazine L'Express published articles claiming that, under the code names "André" and "Dinu", Hernu had been an agent of the Soviet Union. In 2005, the newspaper Le Monde published extracts of a 1986 report by the former chief of the DGSE, Admiral Pierre Lacoste. According to the newspaper, Admiral Lacoste affirmed that the French spies who planted the bombs acted under the orders of Mitterrand himself.
