Gaylord Nelson (1916-2005) was an American politician and governor of Wisconsin who was very interested in the environment and always wanted people to be aware of the importance of taking care of it.
As a senator, in 1970, Gaylord Nelson proposed April 22 as a day for Americans to speak out about the environmental crises, now known as Earth Day. Thus, we can think of Nelson to be the Father of this important day. Moreover, he sponsored numerous conservation bills, including the Wilderness Act, the Wild and Scenic Rivers Act and the Endangered Species Act. Nelson contributed to the passage of environmental laws, such as the Environmental Protection Act and the Wilderness Act.
After his job as a Senator, he served on the Wilderness Society, which was an organization dedicated to conservation. He received the Presidential Medal of Freedom 1995, which is the foremost U.S. civilian decoration, awarded to individuals who have made a meritorious contribution to the security or national interests of the U.S. It is chosen and given by the president of the U.S.
Bibliography:
http://www.nelsonearthday.net/nelson/
https://www.britannica.com/explore/savingearth/gaylord-nelson
https://www.britannica.com/biography/Gaylord-Nelson
https://www.wilderness.org/articles/article/gaylord-nelson