The Endangered Species Act (ESA) was passed almost unanimously by the 93rd Congress of the United States and signed by President Nixon in December 1973. It was a landmark piece of bipartisan legislation that codified the importance of biodiversity to the American people and articulated a commitment to scientific input in societal decisions that affect our collective natural heritage. Thanks to the tireless work of scientists, Indigenous organizations, conservation organizations, government agencies, land managers, and the public, over 1300 species have been protected under the ESA, over 200 of those were likely saved from extinction by listing, and 46 have been recovered. Countless others, including the Greater Sage Grouse, fluvial Arctic grayling, and fishers, have avoided listing altogether thanks to collaborative management strategies stemming from the ESA’s existence. By listing international endangered species, the Act provides a foundation for legislation that restricts trade threatening those species’ survival. The tools needed to implement species recovery under the Act continue to evolve with changing needs and new partnerships, and the ESA continues to be an indispensable force in preventing extinctions over fifty years after it was signed into law.