He was born in Kristiania as a son of Nicolai Andresen Eger (1849–1910) and his wife Marie Frimann Dietrichson (1853–1946).
[1] After one year as deputy judge in Toten District Court, he became a junior solicitor under his father, in the law firm N. A. Eger in 1903.
His law firm was named Mortensen, Eger og Manner, and was co-located in Kongens gate 18 with his brother's company Elkem.
[3] He chaired Christiania Spigerverk, Victoria Linoleumfabrik, Den Ankerske Marmorforretning, Oslo Sparebank,[1] and Norsk Musikforlag.
[2] Eger became a member of the gentlemen's skiing club SK Fram in 1917, and received lifetime membership in 1952.