 After attending the École nationale supérieure des arts décoratifs to complete his education, Frossard began a career in journalism as a cartoonist and columnist.Raised as an atheist, at the age of 20 Frossard converted to Catholicism and was baptized in the chapel of the Sisters of Adoration on 8 July 1935.He explained his conversion in the title of his 1969 bestseller "Dieu existe, je l'ai rencontré" ("God Exists, I Met Him").