Final answer:
Theodore Roosevelt is the Progressive president renowned as a conservationist for safeguarding approximately 230 million acres of wilderness, contributing to the establishment of multiple national parks and forests.
Step-by-step explanation:
The Progressive president best known as a conservationist for his efforts to preserve lands for future generations was Theodore Roosevelt. Roosevelt, an avid outdoorsman, established numerous national wildlife refuges, national parks, and over 150 national forests. His preservation efforts were significantly supported by placing 230 million acres of public land under protection. He was greatly influenced by naturalists like John Muir and worked alongside Gifford Pinchot, the first chief of the U.S. Forestry Service, to promote the efficient, scientifically-informed management of natural resources. While their approaches differed, with Pinchot favoring sustainable use and Muir advocating total preservation, Roosevelt's comprehensive actions solidified his reputation as a leader in environmental conservation.