Prince of Anhalt-Dessau, son of Leopold II Maximillian of Anhalt-Dessau (1700-1751) and Giesela Agnes of Anhalt-Köthen (1721-1751).
Boswell presented a letter from the Count d'Anhalt to Johann Georg at the court of Dessau on September 24, 1764. He was also introduced to Johann Georg's brother Albrecht and their three sisters. According to Boswell, the two princes "spoke only German, so that I had difficult conversation of it. However, I did so well that I was liked, and I was honoured with the distinction of being offered one of the Prince's horses to go a-hunting with, which I most thankfully accepted".
On September 27, he played the card game of Faro with the Prince and his sister, Marie, as well as a Gentleman of Brandenburg (a canon of Halberstadt), afterwards noting that "I lost six écus. I am always unlucky at play, and always keen".