Johann August Eberhard was born in Halberstadt, Lower Saxony, in 1739, the son of a teacher and choral director. After studying theology, philosophy, and classical philology at the University in Halle, he became a tutor for Baron von der Horst's eldest son back in Halberstadt. In 1763 he followed the Baron to Berlin, where he met Moses Mendelssohn, Friedrich Nicolai, and other leading proponents of the Enlightenment. While employed first by the Baron and then as a pastor in Charlottenburg, he wrote two works, in 1772 and 1776, that garnered widespread attention and led to his appointment in 1778 to a professorship of philosophy in Halle, where he remained for the rest of his life, publishing prolifically in philosophy, aesthetics, and theology. In 1786 he was elected an external member of the Academy of Sciences in Berlin, while the theology faculty in Halle awarded him a doctoral degree in 1808 for his theological writings. He died in 1809.

Eberhard's first publication, in 1772, was titled Die neue Apologie des Sokrates (The New Apology of Socrates) and supported the Enlightenment cause by criticizing, among other things, the doctrine of the damnation of the heathens, the orthodox Lutheran interpretation of original sin, and the notion of eternal punishment. His next writing, Allgemeine Theorie des Denkens und Empfindens (Universal Theory of Thinking and Sensing), was selected by the Academy of Sciences in Berlin as the winner of its annual Prize Essay question in 1776.