He was one of the first to use the term "Golden Age of Culture" to refer to the 1800s, and his focus on bringing Danish literature to the public earned him great popularity.

Andersen was instrumental in the development of the School of Radio, as a means of disseminating public education to prevent loss of cultural identity and treasures.

He won the University's Gold Medal in Nordic philology in 1891[2] and took his doctorate in 1896 with his thesis Guldhornene (The Golden Horns).

[2] Andersen began to write around 1893, with such pieces as Danske Studier (1893), Poul Møller, hans Liv og Skrifter (1894), Adam Oehlenschläger, I—III (1894–1900), Litteraturbilleder I—II (1903, 1907), among others.

[2] Andersen later returned to Møller (1904) and Oehlenschläger, (1917) and wrote smaller works on Frederik Paludan-Müller, Henrik Pontoppidan, and Vilhelm Topsøe.

[4] He was the first to use the term "Golden Age of Culture", to refer to the 1800s[3] and his analysis of subjects in that period built up Danish literary history with such works as his three volumes on Ludvig Holberg—Ludvig Holberg paa Tersløsegaard (1904), Holberg billedbog, billeder af Vilhelm Marstrand (1922) and Mindeblad fra Holberg-Samfundets Opførelse af Philosophus udi egen Indbildning (1924)—; his two volumes on Erasmus—Tider og typer af dansk aands historie (1907) and Det attende aarhundrede Gyldendalske (1909)—; his two volumes on Goethe—Det nittende aarhundredes sidste halvdel (1916) and Tider og typer af Dansk aands historie.

[3] Andersen traveled the country and was popular for his readings and lectures on literature which he presented on Danmarks Radio.