Johann Conrad Kern (born June 11, 1808, Berlingen, Thurgau, Switz.—died April 14, 1888, Zürich) was a longtime Swiss minister to France and one of the authors of the Swiss federal constitution of 1848.
A lawyer and doctor of jurisprudence, Kern was, after 1837, the guiding spirit of Thurgau’s cantonal government, especially in the administration of justice. As deputy to the national Diet, he was almost alone in opposing (1838) the extradition of Louis-Napoléon Bonaparte, the nephew of Napoleon, who was trying to overthrow the French government. He combatted the clericalist policies of the dissident Sonderbund league of seven Catholic cantons, ultimately proposing its suppression by force (November 1847).
Following the ensuing Sonderbund War, Kern joined with Henri Druey of Vaud in drafting a new federal constitution (1848) and, after its ratification, served as president of the Federal Supreme Court (Bundesgericht). He was sent to Paris to persuade the French government to mediate in the Neuchâtel controversy (1857), in which the Prussian king Frederick William IV renounced his rights to the canton. Kern remained as Swiss minister to France until 1883.