Motzfeldt was naval cadet at
Fredriksvern Norwegian naval base in 1826. He was a second lieutenant by 1841, then First Lieutenant in 1852. He entered the
Norwegian Parliament in 1857. He was Minister of the Navy and Minister of Postal Affairs in 1860, member of the Council of State Division in
Stockholm 1860–1861, and Minister of the Navy in 1861. From 1870 to 1885, he was elected as a member of Parliament from Jarlsberg og Laurvigs Amt (now
Vestfold). ==Personal life==