By 1876 he was back in England, where he found a job with Hansard, which produces the official verbatim record of Parliament, and he spent the rest of his life in this occupation. Direct descendants of Ebenezer Howard include his cricket manager grandson Geoffrey Howard as well as his great great grandson, the pedagogue George Colin Howard and his daughter Leah Elisabeth Howard.
One result was his book (1898) titled To-Morrow: A Peaceful Path to Real Reform, which was reprinted in 1902 as Garden Cities of To-Morrow. This book offered a vision of towns free of slums and enjoying the benefits of both town (such as opportunity, amusement and high wages) and country (such as beauty, fresh air and low rents). He illustrated the idea with his famous Three Magnets diagram (pictured), which addressed the question 'Where will the people go?', the choices being 'Town', 'Country' or 'Town-Country' - the Three Magnets.
It called for the creation of new suburban towns of limited size, planned in advance, and surrounded by a permanent belt of agricultural land. These Garden cities were used as a role model for many suburbs. Howard believed that such Garden Cities were the perfect blend of city and nature. The towns would be largely independent, and managed and financed by the citizens who had an economic interest in them.
His ideas attracted enough attention and financial backing to begin Letchworth Garden City, a suburban garden city north of London. A second garden city, Welwyn Garden City, was started after World War I. His contacts with German architects Hermann Muthesius and Bruno Taut resulted in the application of humane design principles in many large housing projects built in the Weimar years. Hermann Muthesius also played an important role in the creation of Germany's first garden city of Hellerau in 1909, the only German garden city where Howard's ideas were thoroughly adopted.
The creation of Letchworth Garden City and Welwyn Garden City were influential in the development of "New Towns" after World War II by the British government. This movement produced more than 30 communities, the first being Stevenage, Hertfordshire (about halfway between Letchworth and Welwyn), and the last (and largest) being Milton Keynes, Buckinghamshire. Howard's ideas also inspired other planners such as Frederick Law Olmsted II and Clarence Perry. Walt Disney used elements of Howards's concepts in his original design for EPCOT (Experimental Prototype Community of Tomorrow).
Howard was an enthusiastic speaker of Esperanto, often using the language to give speeches.