Isaac Maarsen took his bachelor's degree in classical literature and obtained credentials as a moreh at age 22. He taught at the Nederlandsch-Israëlitisch Seminarium in Amsterdam. In 1919 he became a rabbi in Amsterdam, and in 1925 he was appointed chief rabbi in The Hague. He continued to serve in this position until his deportation. He vehemently opposed mixed marriages and the reform movement within Judaism.
Maarsen was particularly interested in scholarly research. He wrote a textual study on the Pentateuch commentary by Mozes Nachmanides, critiques of Rashi's explanations, responsa as sources on the history of Jews in the Netherlands, etc. He published articles in Hebrew in Jewish scholarly journals.
M.H. Gans, Memorboek. Platenatlas van het leven der joden in Nederland van de middeleeuwen tot 1940 (6e bijgewerkte druk; Baarn 1988) 803
Isaac Maarsen was a governor at the Israëlitisch Oude mannen- en vrouwenhuis (Jewish home for the elderly) in The Hague.
Records of the Israëlitisch Oude mannen- en vrouwenhuis (Jewish home for the elderly) in The Hague; municipal archive in The Hague.