Around 1830 he was appointed chief customs surveyor in Farsund.

Their son Johan Christian Tandberg Castberg became a customs surveyor and politician.

He worked as an attorney in Sandefjord, before his appointment as a customs surveyor in Brevik in 1856.

He was elected to the Norwegian Parliament in 1874 and 1877, representing the constituency of Fredrikshald, where he worked as a customs surveyor.

Spending his professional life as a customs surveyor, he was mayor of the cities Brevik and Skien, and served three terms in the Norwegian Parliament.