After having been successively Repetent in the University of Göttingen and teacher in the public schools of Dortmund (Westphalia) and Altdorf (Bavaria), he was appointed second professor of theology at the University of Altdorf in 1785, then promoted to a chair in Jena in 1804, where he succeeded Griesbach in 1812 and remained until his death.

[1] At Altdorf, Gabler published (1791–93) a new edition, with introduction and notes, of Eichhorn's Urgeschichte.

This was followed, two years later, by a supplement entitled Neuer Versuch uber die mosaische Schopfungsgeschichte.

He also wrote many essays characterized by critical acumen, and which had considerable influence on the course of German thought in various issues within theology and Biblical studies.

Hänlein (1762–1829), Christoph Friedrich von Ammon and Heinrich Eberhard Gottlob Paulus, and afterwards as sole editor; from 1801 to 1804 of the Journal für theologische Litteratur; and from 1805 to 1811 of the Journal für auserlesene theologische Litteratur.