The prominent figure famed for their role in the establishment of the United Nations is Harry S. Truman. As President of the United States from 1945 to 1953, Truman was instrumental in supporting the UN's formation in response to the devastation of World War II. His vision sought to promote international cooperation, prevent future conflicts, and foster global peace. Truman's leadership during this transformative period laid the groundwork for post-war diplomacy and the UN's ongoing role in world affairs.