Muir convinced Johnson that the area could only be saved if it was incorporated into a national park. Johnson's publication of Muir's exposés sparked a bill in the U.S. Congress that proposed creating a new federally administered park surrounding the old Yosemite Grant. Yosemite National Park became a reality in 1890.

Yosemite became a national park because of an unprecedented movement to preserve its unique geological features and ancient Giant Sequoia trees from commercial exploitation. The process began with the Yosemite Grant of 1864, signed by Abraham Lincoln, which was the first time in history a government set aside land specifically for public use and preservation. Figures like John Muir, a passionate naturalist, argued that the Sierra Nevada wilderness was a spiritual necessity for humanity and needed federal protection from sheep grazing and logging. Muir's advocacy, combined with the stunning photography of Carleton Watkins which showed the beauty of the valley to leaders in Washington D.C., eventually led to the official establishment of Yosemite National Park on October 1, 1890. Later, in 1903, Muir took President Theodore Roosevelt on a famous camping trip in the park, which solidified the President's commitment to the conservation movement. The goal was to ensure that iconic landmarks like El Capitan and Half Dome remained "inalienable for all time," protecting the ecosystem for future generations to study and enjoy.