Eastman, a 1951 graduate of Colby who later earned a degree from the Fletcher School of Law and Diplomacy at Tufts, has had a long diplomatic career which included posts in Europe, Asia, Africa, and the Middle East. After his retirement he settled in southern Maine where he is Chairman of the Sanford Historical Committee, President and Founder of the Sanford-Springvale Historical Society, and creator of the Sanford-Springvale Historical Museum. He is the author of five books on local history, a long-time trustee of Maine Historical Society and actively involved in local and state-wide historic preservation. He has been a collector of old and rare books all of his adult life.