He was born in Sandefjord as a son of ship-owner and merchant Søren Lorents Christensen (1810–1862) and Othilie Juliane Kruge (1820–1903).
[1] Christensen became an officer in 1870, and after attending the Central School in Kristiania and Stockholm in 1874–1875 he reached the rank of Premier Lieutenant.
His main career was in Norway, though, and via Captain in 1889 he reached the rank of lieutenant colonel in 1902.
[1][2] He was among the founders of the interest organization Norges Forsvarsforening in 1886, was active here, and wrote prolifically for the reconstruction and expansion of Norway's armed forces.
Pieces include Om den norske Hærs Krigsdygtighed (1880), Nationen og Armeen (1898), Infanteriets øvelser og sagkyndigheden (1898), Legemsøvelser i folkeskolen (1900) and Forsvarets Genrejsning (1901).