Benson was born in Salem, MA, on 24 March 1862. He was the second of six children, all of whom were encouraged by their parents to learn by experimentation. In this vein, while his siblings dismantled their mother's sewing machine and constructed lightning rods, he began painting birds in his teens. During these years he explored the marshes around Salem, both on foot and in small boats, shooting and sketching waterfowl. His formal education in art commenced when he was nineteen with Otto Grundeman, Frederic Crowninshield, and others at the School of Painting and Drawing of the Museum of Fine Arts, Boston (MA), where he met several future fellow members of the Ten American Painters (a group that split from the Society of American Artists in 1898 out of dissatisfaction with its standards) such as Robert Reid (qv) and Edward Simmons, as well as Edmund C. Tarbell (qv) and fellow Salem native John Redmond. Benson and Redmond began teaching drawing classes in Salem two evenings a week in 1882. In 1883, after a trip to Cuba with his father, Benson went with his friend and Museum School classmate Joseph Lindon Smith to France, where he studied in Paris at the Académie Julian under Jules Lefebvre and Gustave Boulanger and summered in Concarneau, a village in Brittany. During this period he also met John Singer Sargent (qv) and Willard Leroy Metcalf (qv), both of whom numbered among his closest friends.
Upon his return in 1885 Benson worked as a portrait painter in Salem and taught in Portland, ME, for two years. He married Ellen Peirson, a friend of his sister's whom he had also known in Concarneau, in 1888. In 1889 he began teaching at the School of Painting and Drawing of the Museum of Fine Arts, Boston. Benson became joint head, with Tarbell, of the school in the following year; he remained in that position until 1913, when he, Tarbell, and others resigned their positions after a disagreement with the governing council as to how to run the school. During the same period he painted in Dublin, NH, where he worked with Abbot Handerson Thayer (qv); Newcastle, NH, where he and Tarbell taught a summer open-air painting class from 1893 to 1898; Eastham, Cape Cod, MA, where in 1893 he purchased a house with two of his brothers-in-law as a hunting retreat; and North Haven Island, ME, where he spent summers with his wife and children beginning in 1901.
Benson attained his initial success as a portrait and figure painter, using interior and exterior compositions, for which he used both professionals and his children as models. While he never abandoned this sort of painting, in 1912 he began depicting game birds and waterfowl with greater frequency. In addition to painting in oils, he often drew in ink wash and composed in watercolor. At the same time he took up etching, in which he had dabbled with some success in 1882 but had not pursued since. His first known exhibition of a waterfowl scene was Swan Flight, which he showed at the St.Botolph Club in Boston in 1894. He is first known to have placed human figures in his sporting works in 1906, although it was 1914 before he started doing so regularly. His lifelong enthusiasm for angling and wingshooting provided him with the experience necessary to make such works accurate in every regard. His etchings in particular proved so popular that he nearly exhausted himself on more than one occasion in trying to meet demand. He produced over 350 individual plates in his lifetime, and a complete set of etchings and drypoints printed from these plates is in the collection of the Boston Public Library. He also made seven lithographs, of which six were wildfowl subjects, but found he had little interest in the medium. After 1921 he began working more extensively in watercolors, with the result that he was able to paint scenes from the shooting and fishing trips that he regularly took in Canada and the eastern United States. During and after the 1920s his sporting scenes attained considerable popularity. In 1935 Jay Norwood "Ding" Darling (qv) asked Benson to design the second of the Federal Duck Stamps; the result, done from his wash drawing Canvasbacks, is the rarest example of that series.
Benson was a member of the Chicago (IL) Society of Etchers and, in New York City, the National Academy of Design, the National Institute of Arts and Letters, the National Association of Portrait Painters, the Society of American Etchers, the American Academy of Arts and Sciences, and the Ten American Painters. He exhibited several works at the Pennsylvania Academy of the Fine Arts in Philadelphia, including Flying Merganser in 1920, Leaping Salmon in 1923, and Great White Herons in 1934. He exhibited somewhat less frequently at the National Academy of Design; among pictures shown there was Bald Eagles, in 1942. At the Art Institute of Chicago he showed numerous paintings, such as The Fox Hunter in 1915, Wood Duck Pond in 1923, The Crow in 1924, and Grouse Flying in 1938. He received medals for exhibitions at the Pennsylvania Academy of the Fine Arts; the Art Institute of Chicago; the Philadelphia Watercolor Society; the Corcoran Gallery of Art in Washington, DC; the World's Columbian Exposition in Chicago, IL, in 1893; the Paris Exposition in 1900; the Pan-American Exposition in Buffalo, NY, in 1901; the Louisiana Purchase Exposition in St. Louis, MO, in 1904; and the Sesqui-Centennial Exposition in Philadelphia in 1926. He also exhibited at the Royal Academy of Arts in London, England; the Carnegie Institute in Pittsburgh, PA; the Boston Art Club; and the Society of American Artists and the American Watercolor Society, both in New York City. His paintings and etchings were in high demand for exhibition and sale; he had numerous one-man and joint shows at various galleries, and on several occasions found himself unable to fulfill a request for paintings to exhibit because everything was either sold or promised elsewhere. Institutions holding his work include the Carnegie Institute; the Buffalo (NY) Academy of Fine Art; the Rhode Island School of Design in Providence; the Art Institute of Chicago; the Metropolitan Museum of Art in New York City; the Fogg Museum at Harvard University in Cambridge, MA; the Museum of Fine Arts, Boston; the Corcoran Gallery of Art in Washington, DC; the Peabody-Essex Museum in Salem; the Los Angeles (CA) County Museum of Art; and the Addison Gallery of American Art at Phillips Academy in Andover, MA, among many others. His murals of the Three Graces and the Four Seasons are in the Library of Congress in Washington, DC.
Benson died in Salem, MA, on 15 November 1951.