He studied at Göttingen, where he took the degree of doctor Of medicine; and he established his reputation by the dissertation, De irritabilitate (1751). After travelling in the Netherlands and France, he practised as a physician in his native place, and here he wrote Über die Einsamkeit (1756, emended and enlarged, 1784-85) and Vom Nationalstolz (1758). These books made a great impression in Germany, and were translated into almost every European language. They are now only of historical interest.
In Zimmermann's character there was a strange combination of sentimentalism, melancholy and enthusiasm; and it was by the free and eccentric expression of these qualities that he excited the interest of his contemporaries. Another book by him, written at Brugg, Van der Erfahrung in der Arzneiwissenschaft (1764), also attracted much attention. In 1768 he settled at Hanover as private physician of George III with the title of Hofrat. Catherine II invited him to the court of St Petersburg, but this invitation he declined.
He attended Frederick the Great during that monarch's last illness, and afterwards issued various books about him, of which the chief were Über Friederich den Grossen und meine Unterredung mit ihre kurz vor seinem Tode (1788) and Fragmente über Friedrich den Grossen (1790). These writings display extraordinary personal vanity, and convey a wholly false impression of Frederick's character. Zimmermann died at Hanover on the 7th of October 1795.
See A Rengger, Zimmermann's Briefe an einige seiner Freunde in der Schweiz (1830); E Bodemann, Johann Georg Zimmermann, sein Leben und Usher ungedruckte Briefe an ihn (Hann., 1878); and R Ischer, Johann Georg Zimmermann's Leben und Werke (Berne, 1893).
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