 He was chief editor of the series "Aschehougs verdenshistorie", published from 1953 to 1958, and of the series "Vårt folks historie", published from 1961 to 1964.After the death of his brother he had taken over a profitable advertising agency established by his brother.Dahl is remembered for his generous donations to cultural purposes, in particular the funding of "", a series of classical books translated into Norwegian language.