He was 16 and thus considered underage, and his uncles Prince Gundakar and Maximillian acted as regents until 1632.

After the Thirty Years' War Karl effectively restored his dominions economically.

[2] He formed the early plans for Plumlov Castle, which in fact his son the future Hans-Adam I oversaw the construction of.

Karl married his niece, Princess Johanna Beatrix von Dietrichstein-Nikolsburg (c. 1625 – 26 March 1676) on 6 August 1644.

They had nine children: Karl Eusebius plays a prominent role in several of the works in the 1632 series of alternative history novels and stories.