Denis Hayes (1944- ) is a leading environmental activist and proponent of Solar power. He rose to prominence in 1970 as the coordinator for the first Earth Day.

Denis Hayes was born in Wisconsin in 1944, but mainly raised in the small town of Camas, Washington. His experiences growing up in the Pacific Northwest instilled a lifelong love of nature. He received his undergraduate degree in history from Stanford University, where he was president of the student body and an activist against the Vietnam War. During those years, he spent significant time backpacking to remote corners of the world.

Hayes later enrolled at the Kennedy School of Government at Harvard University. He left Harvard to join with Senator Gaylord Nelson to organize the first Earth Day. The first Earth Day (April 22, 1970) had participants and celebrants in two thousand colleges and universities, about ten thousand primary and secondary schools, and hundreds of communities. It is believed that some 20 million demonstrators participated.

Hayes served as international chairman for Earth Day's anniversaries in 1990 and 2000. Internationally, he is recognized for expanding the Earth Day Network to more than 180 nations. It is now the world’s most widely observed secular holiday. Hayes continues to chair the board of the international Earth Day Network.

During the Carter Administration, Hayes became the Director of the federal National Renewable Energy Laboratory. He later returned to Stanford and obtained his Juris Doctor degree.

Since 1992, Hayes has been president of the Bullitt Foundation in Seattle, Washington. By mobilizing the resources of The Bullitt Foundation, Hayes intends to make the Pacific Northwest the best-educated, most environmentally aware, most progressive corner of America—a global model for sustainable development. Also in Seattle are Hayes' wife, Gail Boyer Hayes (daughter of Paul D. BoyerBoyer" target="_blank">http://en.wikipedia.org/wiki/Paul_Boyer), and daughter, Lisa A. Hayes (a Seattle lawyer defending the _Tent City 4 (King County, Washington).

Over Hayes' career, he has been a visiting scholar at the Woodrow Wilson Center, a senior fellow at the Worldwatch Institute, an adjunct professor of engineering at Stanford University, and a Silicon Valley lawyer. He has served on dozens of governing boards, including those of Stanford University, the World Resources Institute, the Federation of American Scientists, The Energy Foundation, Children Now, the National Programming Council for Public Television, the American Solar Energy Society, Greenpeace, CERES, and the Environmental Grantmakers Association.

Hayes has received the national Jefferson Medal for Outstanding Public Service as well as the highest awards bestowed by the Sierra Club, The Humane Society of the United States, the National Wildlife Federation, the Natural Resources Council of America, the Global Environmental Facility of the World Bank, the interfaith Center for Corporate Responsibility, and the American Solar Energy Society. Time Magazine has named him as “Hero of the Planet.”http://www.time.com/time/archive/preview/0,10987,990846,00.html