Professor at Göttingen.
Educated at Halle (Magister, 1739). Traveled extensively in Holland and England (1741). Lectured on the Bible, Semitic languages, classics, and natural history at Halle. Joined philosophical faculty at Göttingen (1745-91); became one of the foremost teachers of Semitic languages in Europe. Published numerous works of Biblical criticism and linguistics. Director of the Königliche Gesellschaft der Wissenschaften (1761-70). Met Franklin and Sir John Pringle during their German tour (1766) and subsequently corresponded with Pringle.
Son of Christian Benedict Michaelis of Halle; his father and great-uncle were distinguished Biblical scholars. Married (1) Joh[anna?] Schachtrup (1749); one son. Married (2) Louise Schröder (c. 1759); nine children.