Hagedorn's father was the Danish ambassador in Hamburg, and the young Hagedorn in 1729 became an unpaid private secretary to the Danish ambassador in London. He returned to Hamburg in 1731 and two years later was appointed secretary to the English trading company Englischer Hof, a position that gave him a great deal of leisure.

Although he is usually grouped with the German Anacreontic poets, his model was Horace, rather than the Greek poet Anacreon, and his poetry was not limited to the love and drinking songs characteristic of the Anacreontics. His best and most popular works appeared in Versuch in poetischen Fabeln und Erzählungen (1738; “Attempt at Poetic Fables and Tales”) and Oden und Lieder, 3 vol. (1742–52; “Odes and Songs”). These fables and tales in verse, influenced by the French poet Jean de La Fontaine, are characterized by neatness of form, graceful lightness of touch, and a feeling for rhythm that sets Hagedorn apart from other poets of his time.