University students, as future decision-makers and practitioners, play a pivotal role in advancing carbon neutrality by 2060. Their awareness and behaviors are highly malleable during university education, with long-term impacts extending beyond campus boundaries. Using Peking University as a case study, this research quantifies the carbon footprint of students' lifestyles, develops a structural equation model (SEM) of low-carbon behavior mechanisms, and evaluates lifestyle-based emission reduction scenarios. Results show that food and transportation are the major contributors to students’ carbon footprints, reflecting a paradox of “high support but low motivation” toward low-carbon practices. While changes in individual cognition are necessary, they yield limited mitigation benefits. Scenario simulations demonstrate that synergistic interventions from campuses, communities, and broader society can amplify emission reductions by up to 40 %, offering a scalable pathway for universities to pioneer behavior-driven decarbonization. This study thus provides both empirical evidence and a practical framework for building zero-carbon campuses and cultivating societal transitions toward sustainability.