He became royal physician to the mentally ill King Christian VII of Denmark and a minister in the Danish government.

Born at Halle an der Saale and baptized at St. Moritz on 7 August 1737, Struensee was the third child of six born to Pietist theologian and minister Adam Struensee (baptized in Neuruppin on 8 September 1708 – Rendsburg, 20 June 1791) and his wife Maria Dorothea Carl (Berleburg, 31 July 1716 – Schleswig, 31 December 1792).

The elder Struensee attended the University of Halle and served in a number of pastoral postings before being appointed Royal General Superintendent of Schleswig and Holstein between 1760 and 1791.

His parents moved to Rendsburg in 1760 where Adam Struensee became first superintendent (comparable to bishop) for the duchy, and subsequently superintendent-general of Schleswig-Holstein.

Struensee was ambitious and petitioned the Danish government through Minister of Foreign Affairs Count Johann Hartwig Ernst von Bernstorff for funds.

[editorializing] He tried his hand at writing Enlightenment treatises and published many of them in his journal Zum Nutzen und Vergnügen ("For benefit and enjoyment").

At first Caroline Matilda disliked Struensee, but she was unhappy in her marriage, neglected and spurned by the king, and affected by his illness.

[citation needed] Over time her affection for the young doctor grew and by spring 1770 he became her lover; a successful vaccination of the baby crown prince in May still further increased his influence.

[4] Struensee was very involved with the upbringing of the Crown Prince Frederick VI along the principles of Enlightenment, such as outlined by Jean-Jacques Rousseau's challenge to return to nature.

He also took Rousseau's advice about cold being beneficial for children literally, and the Crown Prince was thus only sparsely clothed even during wintertime.

However, as the royal court and government spent the summer of 1770 in Schleswig-Holstein (Gottorp, Traventhal, and Ascheberg) his power grew.

[4] Critics of Struensee thought that he did not respect native Danish and Norwegian customs, saw them as prejudices and wanted to eliminate them in favour of abstract principles.

[9] What incensed the people most against him was the way in which he put the king completely on one side, and the feeling was all the stronger as, outside a very narrow court circle, nobody seems to have believed that Christian VII was really mad, but only that his will had been weakened by habitual ill usage[clarification needed].

[4] Struensee's relations with the queen were offensive to a nation which had a traditional veneration for the royal House of Oldenburg, and Caroline Matilda's conduct in public scandalized the populace.

Christian VII along with his queen, Struensee, Brandt, and members of the royal court, spent the summer of 1771 at Hirschholm Palace north of Copenhagen.

A palace coup took place in the early morning of 17 January 1772, Struensee, Brandt and Queen Caroline Matilda were arrested in their respective bedrooms, and the perceived liberation of the king, who was driven round Copenhagen by his deliverers in a gold carriage, was received with universal rejoicing.

He defended himself with considerable ability and, at first, confident that the prosecution would not dare to lay hands on the queen, he denied that their liaison had ever been criminal.

However, as a commoner who had imposed himself in the circles of nobility, Struensee was condemned as being guilty of lèse majesté and usurpation of the royal authority, both of which were capital offences according to Paragraphs 2 and 26 of the Kongelov.