The son of a pastor, Gellert was reared in a poor and extremely pious family. After working as a tutor, he studied at the University of Leipzig, where he became a Privatdozent (unsalaried lecturer) in 1745 and a professor in 1751. Popular both for his work and for his personality, his lectures on poetry, rhetoric, and ethics were exceptionally well attended.

Gellert was best known for his Fabeln und Erzählungen (1746–48; “Fables and Tales”), a collection of naïvely realistic fables and moralizing stories charming for their directness and simplicity. These tales not only had many readers among the common people but also influenced other fable writers. Equally popular was Geistliche Oden und Lieder (1757; “Spiritual Odes and Songs”), poems and hymns that combined religious feeling with the rationalism of the Enlightenment. The most famous of these, “Die Himmel rühmen des ewigen Ehren” (“The Heavens Praise the Eternal Glories”) and “Die Ehre Gottes aus der Natur” (“The Glory of God in Nature”), were later set to music by Beethoven (Beethoven, Ludwig van) and still appear in hymnbooks. Gellert also wrote a sentimental novel, Das Leben der schwedischen Gräfin von G (1748; “The Life of the Swedish Countess of G”), which combined the late 17th-century novel of exotic adventure with the character novel of modern literature and introduced the moralistic “family novel” in German literature.