He began his studies in 1884 and published his first collection of poetry, Naturbørn, which attracted attention due to its daringness and bold eroticism along the lines of Emil Aarestrup's work.

He first began to make a name for himself through two partially symbolic, partially realistic idylls about life in market towns, "Unge Bander" (1894) and "Kitty" (1895), which through a blend of prose and poetry as well as playfulness and grace captivated readers (particularly his introduction to "Unge Bander": "Frøken Regnvejr", likely his most significant work [revised edition 1912]).

[3] Claussen lived in Paris for a number of years and published several smaller books ("Trefoden" [1901], "Djævlerier" [1904], "Eroter og Fauner" [1910]).

After returning to Denmark, he published a comprehensive and characteristic collection of poetry, Danske Vers, which defines the capricious nature of his body of work.

[4] Claussen and author Johannes Jørgensen co-wrote the journal Taarnet as part of the Danish Symbolism movement.