Ellis served in the Air Force during the Korean War, and graduated from the Honors College, Michigan State University. Following E.B. White's advice, Ellis spent "the first forty years of his life doing something else" before turning to writing. He headed the Crime Analysis Unit of the St. Louis Police Department; worked as a senior researcher for good government organizations in Hartford and Boston; and headed the Planning Bureau of the Mass. State Police. After, he worked in management positions with the U.S. Justice, Treasury, and Labor departments and was appointed a New England regional director of the Department of the Interior. In addition to his biography of Captain "Mad Jack" Percival and histories of the War of 1812 and the Cape Cod village of West Barnstable, he is a frequent contributor to periodicals and professional journals, and he contributed to two police administration textbooks.