After graduating, he started working as a lawyer in Antwerp. Between World War I and World War II Nico Gunzburg lectured at the University of Ghent, mainly on criminology. Politically he was one of the supporters of the dutchification of the University of Ghent. He took the initiative to start a new committee to discuss the matter. The commission started officially in 1919 and defended the bill of 1911 of Louis Franck-Van Cauwelaert-Huysmans which, after many years of transitional measures, aimed at the usage of a single language (Dutch) for education in Flanders. In 1920 he established the Centrale Jewish Welfare Organisation which became the Royal Society of Jewish Welfare known as "The Centrale".