[1] Born in Berlin to very poor parents, Herz was destined for a mercantile career, and in 1762 went to Königsberg, East Prussia.

He soon gave up his position as clerk and attended the University of Königsberg,[2] becoming a pupil of Immanuel Kant, but was obliged to discontinue his studies for want of means.

On 21 August 1770, he travelled from Berlin and acted as respondent when Kant presented his Inaugural dissertation[3] at the University of Königsberg for the post of ordinary professor.

Beginning in 1777, he delivered public lectures on medicine and philosophy, which were well attended by the students and the principal personages of the Prussian capital.

In 1791, he received the title of Professor of Philosophy at the academy and that of "Hofrath", but lectured only for a few years, giving most of his time to his medical practice.