After receiving a M.F. from Harvard Forest School, Robert Marshall spent five years as a silviculturist in the northern Rockies and Alaska. In 1933, he was appointed the Director of Forestry for the office of Indian Affairs, U.S. Department of the Interior. He later returned to the Forest Service as the Chief of the Division of Recreation and Lands, where he influenced Forest Service policies regarding wilderness land preservation and recreation. In 1935, Marshall joined with Aldo Leopold and a small group of other prominent conservationists to found the Wilderness Society, where he served on its executive committee. He wrote a number of books and pamphlets on forest topics, public policy, and on his travels in Alaska.