Dow went to Paris for his early art education, studying at the Académie Julian under the supervision of the academic artists, Gustave Boulanger and Jules Joseph Lefebvre, between 1880 and 1888. He accepted commissions for posters and other commercial work. In 1895, he designed the poster to advertise the Journal of Modern Art and in 1896, he designed the poster for an exhibition of Japanese prints.
After his return to the United States, over the course of his career Dow taught at three major American arts training institutions, beginning with the Pratt Institute from 1896-1903. He also taught at the New York Art Students League from 1898-1903. In 1900, Dow founded and served as the director of the Ipswich Summer School of Art in Ipswich, Massachusetts. From 1904 to 1922, he was a professor of fine arts at Columbia University Teachers College.