Cappelen acquired the Eidsfos Iron Works at Hof in Vestfold during 1795, and Kongsberg Iron Works on Numedalslågen in 1824. In 1811 he donated 10,000 rigsdaler to the establishment of a University in Christiania (now University of Oslo). He represented Drammen at the Parliament of Norway from 1815. He was decorated Knight of the Order of Vasa in 1825.
