She was born in Christiania as a daughter of banker Andreas Arntzen (1837–1919) and Anna Cathrine Elisabeth Stilling (1845–1918).
From 1900 to 1912 she was a chief nurse at the tuberculosis department at Ullevål, only interrupted by a study trip to England and Scotland in 1902.
From 1915 Ullevål became a national centre of nursing education, with more theoretical testing, systematic practical training and examination.
Together with union leader Bergljot Larsson, she spearheaded the work to institutionalize the nursing education in Norway as a three-year course, although this reform would not passed by Parliament for many years.
[1] Arntzen was proclaimed an honorary member of the Norwegian Nurses' Union and was awarded the King's Medal of Merit in gold.