In 1888, Bailey was appointed chair of Practical and Experimental Horticulture at Cornell University. In 1904, he co-founded the College of Agriculture. In 1907, after giving a speech about the Country-Life Movement, which advocated for improving the lives of people living in rural areas, President Theodore Roosevelt (who heard the speech), appointed Bailey the national chair of the Commission on Country-Life. The Commission proceeded to study the lives of rural Americans and what could be done to improve their living conditions. Bailey wrote the Commission's report in 1909.
Bailey was a prolific writer throughout his life, penning or editing over 200 books that explored a range of topics including plants, farming, and even democracy. During his retirement years, he went on several botanical expeditions to collect plants; he traveled to the Caribbean, Central and South America, and other places. At the age of 92, he was planning a trip to the Congo rainforest but broke his femur in a revolving door. He declined after this but lived for four more years. He died on Christmas Day in 1954.