[1][2] Rochussen was selected to become Minister of Finance by William I in the king's last year of his reign, taking office on 31 July 1840.

[1][2] He was later selected as a special envoy to Brussels, a post which he held for nearly two years and which resulted in him settling inheritance and property issues to the satisfaction of both sides.

[1] Before his departure, former governor general Jean Chrétien Baud recommended that Rochussen take an interest in the Javanese people.

[2] Although Rochussen initially intended to build greater infrastructure in the Indies, he later felt that a full autocracy was necessary and as such instituted severe limitations to press freedom.

A year later, he became the Chairman of the Council of Ministers after fifteen days forming the cabinet in collaboration with Jan Karel van Goltstein.

He served from 18 March 1858 until 1 January 1861, on which date he resigned due to his proposed budget being failed at the house meeting on 14 December 1860.

[1] His grandson, Herman Adriaan van Karnebeek, became mayor of The Hague, Minister of Foreign Affairs, and later President of the League of Nations from 1921 to 1922.