In 1825 he converted to the Evangelical Church in Prussia, and the following year was appointed extraordinary, and in 1828 ordinary, professor in the Berlin University faculty of law.
Before converting, he was a member of the Society for the Culture and Science of the Jews, alongside Joel Abraham List, Isaac Marcus Jost and Leopold Zunz.
Gans, his Hegelian tendencies predisposing him to treat law historically, applied the method to one special branch—the right of succession.
His great work, Erbrecht in weltgeschichtlicher Entwicklung (1824, 1825, 1829 and 1835), is of enduring value, not only for its extensive survey of facts, but for the admirable manner in which the general theory of the slow evolution of legal principles is presented.
The liberality of his views, especially on political matters, drew upon Gans the displeasure of the Prussian government, and his course of lectures on the history of the last fifty years (published as Vorlesungen über die Geschichte der letzten fünfzig Jahre, Leipzig, 1833–1834) was prohibited.