Walter Sedgwick is a long-time forest landowner and conservationist who has worked with many organizations dedicated to land and animals, serving on the Boards of the National Audubon Society, The Nature Conservancy-Florida, Land Trust Alliance, and the Turtle Survival Alliance. He was Chair of Tall Timbers, Bat Conservation International, Island Conservation, and the Pacific Forest Trust. He is currently on the board of the Wildlife Conservation Society..

Walter is co-founder of Island Press and the Red Hills Land Conservancy which is now part of Tall Timbers.  He also helped to found the Turtle Conservation Fund in 2002. With his Walter C. Sedgwick Foundation, he has donated a major collection of Japanese Buddhist sculpture and early Chinese ceramics to the Harvard University Museums.