He was born in Bergen as a son of sailmaker Herman Jæger (1824–1871) and Birgitte Pedersen.

In June 1881 he married Marie Louise Holstad (1853–1931),[1] and their daughter Dagmar Helene Jæger (1889–1979) married Olaf Gjerløw.

[2] He is known for his early monographs on Henrik Ibsen, and for writing the first large Norwegian literary history, Illustreret norsk Literaturhistorie (1896).

[1][3] In 1884 he was a co-founder of the Norwegian Association for Women's Rights.

[4] This article about a Norwegian writer, poet or journalist is a stub.