Attended Stralsund Grammar School before studying in Greifswald, where he got to know Ernst Moritz Arndt. In 1813 he was appointed pastor at St Jacob’s Church in Stralsund. In the following years he wrote books such as Huttens Klage (1816), Sastrows Leben, Wessels Leben (1823–24) and the first volume of the Stralsunder Chronik (1833). Mohnicke gained renown for his translation of Tegner’s Frithiof’s Saga from Swedish into German.