Descended from a long line of nobility, Fénelon began his higher studies in Paris about 1672 at Saint-Sulpice seminary. Ordained a priest in 1676, he was appointed director of Nouvelles Catholiques (“New Catholics”), a college for women who instructed converts from French Protestantism. When King Louis XIV heightened the persecution of the Huguenots (French Calvinists) in 1685 by revoking the Edict of Nantes, Fénelon strove to mitigate the harshness of Roman Catholic intolerance by open meetings with the Protestants (1686–87) to present Catholic doctrine in a reasonable light. While unsympathetic to Protestant belief, he equally repudiated forced conversions.

From his pedagogical experiences at Nouvelles Catholiques, he wrote his first important work, Traité de l'éducation des filles (1687; “Treatise on the Education of Girls”). Although generally conservative, the treatise submitted innovative concepts on the education of females and criticized the coercive methods of his day.

In 1689, with the support of the renowned bishop Jacques-Bénigne Bossuet (Bossuet, Jacques-Bénigne), Fénelon was named tutor to Louis, Duke (duc) de Bourgogne, grandson and heir to Louis XIV. For the prince's education, Fénelon composed his best-known work, Les Aventures de Télémaque (1699), in which the adventures of Telemachus in search of his father, Ulysses, symbolically expressed Fénelon's fundamental political ideas. During the period of his popularity in official circles, Fénelon enjoyed various honours, including his election to the French Academy in 1693 and his selection as archbishop of Cambrai in 1695.

Anxious about his spiritual life, Fénelon sought an answer from the Quietist school of prayer. Introduced in October 1688 to Quietism's leading exponent, Mme Guyon, Fénelon sought from her some means of personally experiencing the God whose existence he had intellectually proved. But his search for spiritual peace was short-lived. Bossuet and other influential people at court attacked Mme Guyon's teaching, and a document investigating Quietism's doubtful orthodoxy even obtained Fénelon's signature. When Bossuet, however, next launched a personal attack on Mme Guyon, Fénelon responded with Explication des maximes des saints sur la vie intérieure (1697; “Explanation of the Sayings of the Saints on the Interior Life”). Defending Mme Guyon's integrity, Fénelon not only lost Bossuet's friendship but also exposed himself to Bossuet's public denunciation. As a result, Fénelon's Maximes des saints was condemned by the pope, and he was exiled to his diocese.