The integration of sustainability in sport has transitioned from a theoretical concept to an operational imperative, demonstrating its practical viability in mass events. Initiatives such as the Lima 2019 Pan American Games and the Paris 2024 Olympic Games reveal replicable strategies: emissions mitigation through certified offsets, a circular economy in infrastructure with energy efficiency certifications, and multi-level governance that connects institutions, athletes, and communities. Transportation emerges as the greatest challenge, accounting for up to 87% of the carbon footprint at mega-events, necessitating innovative solutions in electric mobility and logistics optimization. Simultaneously, spectators’ commitment to responsible consumption and the participation of certified suppliers amplify the sustainable impact. The three-dimensional model—lean preparation, green operations, and a legacy aligned with the Sustainable Development Goals—turns events like Lima 2027 into laboratories for green innovation. Iconic cases, such as Forest Green Rovers, with solar-powered stadiums, vegan food, and recycled uniforms, demonstrate that sporting excellence and environmental resilience are converging goals. Sport, due to its unique cross-cultural reach, acts as a massive catalyst, transforming stadiums into classrooms of planetary awareness and mobilizing behavioral changes in millions of people. Its environmental leadership transcends the symbolic to become a tangible driver of global ecological transition, where top-level competition celebrates not only sporting records but also harmony with the planet.