He was born at Saint-Félix, in Haute-Savoie. In his earliest years he was confided to the care of his brother, a priest in the diocese of Chambéry. In 1810 he was sent to a pensionnat ecclésiastique at Paris. Thence he went to the seminary of St Nicolas de Chardonnel in 1813, and was transferred to the seminary of St Sulpice at Paris in 1820. In 1825 he was ordained priest, and was appointed vicar of the Madeleine at Paris. For a time he was tutor to the Orléans princes. He became the founder of the celebrated academy at St Hyacinthe, and received a letter from Gregory XVI eulogizing his work there, and calling him Apostolus juventutis.
He was elected to the French Academy in 1854, occupying the thirty-eighth chair, becoming leader of the Academy’s "religious party", in which capacity he opposed the election of agnostic intellectuals. Dupanloup resigned in 1875 after Émile Littré, an agnostic, was elected to the Academy.
His imposing height, his noble features, his brilliant eloquence, as well as his renown for zeal and charity, made him a prominent feature in French life for many years. Crowds of persons attended his addresses, on whom his energy, command of language, powerful voice and impassioned gestures made a profound impression. When made bishop of Orléans in 1849, he pronounced a fervid panegyric on Joan of Arc, which attracted attention in England as well as France. Joan of Arc would later be canonized, due partly to Dupanloup's efforts. Before this, he had been sent by Archbishop Aifre to Rome, and had been appointed Roman prelate and protonotary apostolic.
For thirty years he remained a notable figure in France, doing his utmost to arouse his countrymen from religious indifference. He was a distinguished educationist who fought for the retention of the Latin classics in the schools and instituted the celebrated catechetical method of St Sulpice. Among his publications are De l'éducation (1850), De la haute éducation intellectuelle (3 vols., 1866), Œuvres choisies (1861, 4 vols.); Histoire de Jésus (1872), a counterblast to Renan's Vie de Jésus.
In ecclesiastical policy his views were moderate. Both before and during the First Vatican Council, he opposed the definition of the dogma of papal infallibility as inopportune, but after the definition was among the first to accept the dogma.
In the work known as Illustrissimi, a collection of letters written by Pope John Paul I when he was Patriarch of Venice, Dupanloup is one of the "recipients" of the letters. There are 40 letters in all, mainly to people in Italian history and fiction, but also to internationally well known fictional and historical characters such as Pinocchio, Charles Dickens, Hippocrates, and Jesus. Each of the letters tend to be droll and witty, but cleverly turned into a short sermon in order to make a point, whether it is on fashion, pornography, capitalism, or the communications industry.