Born in Fjälkestad, Sweden, Benson immigrated to America in 1852 with his cousin Swain Nelson. After living in Defiance, Ohio, they moved to Chicago in 1855, where Benson worked in the printing department of the Chicago Tribune, and then with Svenska Republikanen. He attended high school, graduating in three years before serving the Union cause in the Civil War. In 1865 Benson assisted Nelson with the survey that undergirded the latter’s plan for Lincoln Park in Chicago. One year later, the partnership of Nelson & Benson was formed. Work on Lincoln Park stretched into the next decade, and a contract allowed the men to rent row boats and sell refreshments in exchange for maintaining the grounds and feeding the zoo animals.
In 1875 Benson was appointed superintendent of Lincoln Park, a post he held for at least fourteen years. He oversaw construction of Lake Shore Drive south of the park and transformed a marshy area north of Fullerton Avenue into lawns and a dredged lake (now the North Pond Nature Sanctuary). He submitted a plan for the grounds of the new campus of Indiana University on the eastern edge of Bloomington around 1884, but the extent of its implementation is unknown. By 1887 the partnership with Nelson had dissolved, and Benson was hired to improve the grounds of the Cook County (Illinois) Normal School in 1890. Soon thereafter he designed the 2.3-acre Hackley Park in Muskegon, Michigan. In 1900 Benson advertised his services as a landscape engineer based in Chicago, offering designs and contracting for parks, cemeteries, and subdivisions. Around that time, he laid out gardens and paths at the 23-acre Smith Park in Menasha, Wisconsin, and worked on the six-acre grounds of Black Point in Lake Geneva, Wisconsin. Benson died at his summer home in Benton Harbor, Michigan, at the age of 72.