Hallowell studied painting with Benson and Tarbell and architecture with Arthur Rotch and Herbert L. Warren. He was a member of the Boston Society of Water Color Painters, the Aquarellists, and the New York Water Color Club. His awards included the Beal prize at the New York Water Color Club, 1904; a gold medal at the St. Louis Exposition, 1904; and a gold medal for water colors, Panama-Pacific Exposition, San Francisco, 1915.