Though Hallett studied abroad in Antwerp and Paris, his sojourn took only eighteen months away from his beloved home in Massachusetts. Originally from Charlestown, Hallett adopted Boston as his home, setting up studios on Court Street, then the Studio Building, and finally the newly finished Fenway Studios by 1907. He painted primarily marine scenes in and around Boston Harbor, along the north shore up to Marblehead, and farther north to Bar Harbor and Mount Desert Island in Maine.
Against his father’s wishes, Hallett became a painter, setting out to capture the distinct beauty of the New England coast in oil and watercolor. He eventually joined a group of active resident artists in the greater Boston area, including William Halsall, Walter Lansil, and William Norton, all of whom had made careers of painting maritime subjects and exhibited regularly at the Boston Art Club in the 1870s. In doing so, these artists helped to establish a wider market for marine painting, and laid the foundation for a lasting acceptance of the genre that would benefit artists to come. Hallett himself was a member of the Boston Art Club, and continued to exhibit his work there until 1909.
His works are held in private collections and at the Brockton Public Library in Brockton, MA and at the Mystic Seaport Museum in Mystic, CT.