Allen studied with Philip Hale and Hermann Dudley Murphy at the School of the Worcester (Massachusetts) Art Museum from 1913 to 1916. As a mature artist, he took for his subjects mountains, farmhouses nestled into hills, picturesque buildings and fishing ports, the seasonal beauties of nature; he rarely introducing figures into his scenes. These landscapes are loose and painterly, yet Allen never strayed far from a realistic rendition.
He maintained a studio in his home in Waban, but ranged widely through New England in pursuit of subject matter, painting at Ogunquit, Maine, East Gloucester, Massachusetts, and in the White Mountains near Jackson, New Hampshire; many summers he worked at the Moody Farm on Mount Monadnock in southern New Hampshire. Allen also taught, taking his students with him on many of his paintings expeditions around northern New England. Among many honors, Allen won the First Landscape Medal at the Boston Tercentenary exhibition in 1930.
Allen worked in several media; in 1945, the Museum of Fine Arts, Dallas, presented an exhibition of his etchings, acquatints, and engravings. He was a member of the Boston Society of Watercolor Painters, serving as its vice president for a time, and also of the Guild of Boston Artists.
Allen was represented by the Vose Gallery, Boston.