Morton built a 30-room mansion. His son, Joy, expanded it to a 52-room mansion that is a look-alike of the White House in what is now Arbor Lodge State Historical Park, Nebraska City, Nebraska. On the surrounding estate, Morton indulged his fascination with trees, planting many rare varieties and heirloom apple trees. Respected as an agriculturalist, Morton sought to instruct people in the modern techniques of farming and forestry. Among his most significant achievements was the founding of Arbor Day. He is also remembered for his support of slavery and his fierce opposition to cutting down healthy trees as Christmas decorations. He became well known in Nebraska for his political, agricultural, and literary activities and from there was appointed as United States Secretary of Agriculture by President Cleveland (1893–1897). He is credited with helping change that department into a coordinated service to farmers, and he supported Cleveland in setting up national forest reservations.