From 1813 to 1815 he was a soldier in the Napoleonic Wars, afterwards working as a lecturer at the University of Jena.
Two of his better known students were Friedrich Wilhelm Ritschl (1806–1876) and Friedrich Haase (1808–1867), the latter having published an edition of Reisig's Vorlesungen über lateinische Sprachwissenschaft (Latin Lectures on Linguistics) in 1839.
Reisig was a classical philologist who is credited with developing a new branch of linguistics known as "semasiology".
He introduced this new discipline because he felt that the study of word-meaning could not be adequately met within the constraints of etymology or syntax.
He felt that semasiology would properly show the development of word-meanings in a logical and historical sense.