German writer and critic who provided valuable guidance to the young writers of the Sturm und Drang (“Storm and Stress”) movement of the late 18th century.

After studying law at Giessen, Merck was appointed first a paymaster at Darmstadt and later an official in the war department for the court of Hesse-Darmstadt. For several years he was influential in German literary circles and sympathetic with the poetic aims of such leading writers as Christoph Friedrich Nicolai (Nicolai, Friedrich), Christoph Wieland (Wieland, Christoph Martin), J.G. von Herder, and J.W. von Goethe (Goethe, Johann Wolfgang von), despite his bitingly sarcastic criticism. Merck helped found the periodical Frankfurter Gelehrte Anzeigen (1772), in which some of Goethe's earliest pieces were published, and contributed to Nicolai's journal, Allgemeine deutsche Bibliothek, and Wieland's Der teutsche Merkur. Merck also wrote many treatises on literature, art, and painting. His letters provide an invaluable source for the literary life of the times.

The deaths of several of his children and the failure of several business enterprises led to his suicide.