Frederik IV's marriage to Anna Sophie divided the royal family and Prince Carl and Princess Sophia Hedwig moved court to Vemmetofte in 1721.

Plessen was, like the Prince and the Princess, inexorable in his view on Queen Anna Sophie and her party which completely dominated the government in Copenhagen, and the king's overtures in 1825 were therefore met with cold air at Vemmetofte.

This hostility and his profound religious beliefs won Plessen the favour of Crown Prince Christian, who immediately included him in the new government upon his ascent to the throne in 1730.

He served as president of the Danish West Indies Company and was a driving force behind the purchase of Saint Croix from France in 173.

[2] He owned the estates Førslev, Harrested, Gunderslevholm, Saltø, Kastrup, Fuglebjerg and Fodby on Zealand and Dronninglund Manor in Jutland.