With the rapid advancement of industrialization and urbanization, the increase in carbon emissions and the continuous deepening of population aging have become two major challenges that hinder the high-quality development of China’s economy. Based on the panel data of 30 provinces in the Chinese Mainland from 2003 to 2020, this paper uses the two-way fixed effect model to investigate the impact mechanism and effect of population aging on carbon emissions. The research results indicate that the aging population has significantly exacerbated regional carbon emissions in China, and a series of robustness tests have also confirmed this conclusion. From a regional perspective, the aging population in developed, coastal, and inland regions has an exacerbating effect on carbon emissions. Developed regions have the highest carbon emissions, followed by inland regions, and coastal regions have the lowest. Underdeveloped regions have emission reduction effects. From the perspective of the mechanism, population aging not only exacerbates regional carbon emissions through consumption structure effects, but also promotes regional carbon emissions through production effects. On this basis, in order to effectively achieve regional carbon reduction, this article proposes a series of policy recommendations from accelerating population policy adjustment, optimizing energy consumption structure, and strengthening cross regional collaborative environmental governance.