He was born in Sørum as a son of leather trader Martin Christofersen (1843–1925) and Caroline Mathea Johnsen (1833–1890).
[2] Christofersen finished his secondary education in 1886 and took the University's admission test in 1887.
He then enrolled in the Norwegian Military Academy, reaching the ranks of Premier Lieutenant in 1892 and Captain 1901.
He was more of a pecuniary strategist than the politically inclined Diesen, leading to professional and personal disagreements during the First World War.
He was later a board member of the nationwide Norwegian Press Association.