Charles Dallet was born in Langres, France, on 18 October 1829.
He joined the Paris Foreign Missions Society in 1850 and was ordained on 5 June 1852.
In 1859, he published there, in English, a work titled Controversial Catechism, or short answers to the objections of Protestants against the true religion.
After returning to France, he classified manuscripts regarding the Catholic Church in Korea—largely the work of the martyred bishop Antoine Daveluy—which provided the material for his Histoire de l'Église de Corée (1874, two volumes).
In 1877, Dallet went back to Asia, this time passing Russia, Manchuria, China and Japan.