Son of Leopold I of Anhalt-Dessau (1676-1747) and Anna Luise Föhse (1677-1745).
He was a sometime Field Marshall in the Prussian army, and acting regent of Anhalt-Dessau from 1751 to 1758, during the minority of his nephew Leopold III. He died in 1769 without issue.
Boswell was introduced to Dietrich by G. H. Berenhorst on September 25, 1764. Boswell “found him a tall, comely old man of sixty-two” and “just one of the old Germans, rough and cordial”. The old Prince then showed Boswell his stables, and they both set out on a hunt together with most of the court of Anhalt-Dessau present in the city on that day.
At the end of the hunt, Dietrich presented Boswell with the stag's foot, noting that it was a “mark of distinction”. Boswell apparently intended to “have it laid up in the museum at Auchinleck” together with an inscription on a plate, but no further mention of it seems to exist, except for a Latin inscription intended for that purpose, in a letter to Boswell from David Dalrymple.
Following a hunt on September 28, Boswell and others again dined with Prince Dietrich, and he this day described the Prince as “a plain, warm-hearted old man”.