Mr. Hales served from 1994 to 2001 as Deputy Assistant Administrator and founding Director of the Global Environmental Center at USAID. During this period, he led the development and implementation of USAID climate change, biodiversity, environment and natural resource, and urban programs operating in more than 80 countries worldwide. During his service he led United States delegations to the World Water Summit and to the City Summit in Istanbul, and represented the United States at Conferences of Parties to various Conventions, including the Framework Convention on Climate Change and the Convention on Biological Diversity, and to the Commission on Human Settlements and the Commission on Sustainable Development.

Mr. Hales served as Deputy Assistant Secretary of Interior for Fish and Wildlife and National Parks during the administration of President Jimmy Carter, and was Director of the State of Michigan's Department of Natural Resources from 1988 - 1991. From 1980 - 1987, he was the Samuel Task Dana Professor of Natural Resources at the University of Michigan. From 1994 - 1996 he was a member of the 56th College of National Lecturers for Sigma Xi, the Scientific Research Society.

Accomplishments include being one of the primary legislative architects of the Redwoods National Park Expansion of 1978, the Alaska National Interest Lands Conservation Act, 1980, and the 1980 Pinelands National Reserve Act. He led Carter Administration efforts leading to the passage of the National Parks and Recreation Omnibus Act of 1978, which doubled the size of the United States National Wild and Scenic Rivers System and the National Trails System. He is co-founder, with Michael Soule of the Society for Conservation Biology, and the first American to serve as the President of the World Heritage Convention. In 2000, he authored the definition of Water Security adopted by consensus at The Hague International Conference on Fresh Water.