In 1759 he was appointed professor at the gymnasium of Erfurt, but relinquished this situation two years later and went to reside in a private capacity at Leipzig, where he devoted himself to philological researches.

In 1787 he received the appointment of principal librarian to the Elector of Saxony at Dresden, where he continued to reside until his death in 1806.

By means of his excellent grammars, dictionary, and various works on German style, he contributed greatly towards rectifying the orthography, refining the idiom, and fixing the standard of his native tongue.

The hint of this work appears to have been taken from a publication with a similar title, published by Konrad von Gesner in 1555, but the plan of Adelung was much more extensive.

The first volume, which contains the Asiatic languages, was published immediately after his death; the other two were issued under the superintendence of Johann Severin Vater (1771–1826).