Plastic pollution has become one of the most pressing environmental issues. It is essential to understand why an individual is or is not supportive of reducing plastics. This study aims to investigate the dynamics behind residents’ plastic reduction attitudes from the lens of the Big Five personality traits. A sample of 521 residents in China was recruited and analyzed for this study. The results indicate that the Conscientiousness personality type is a reliable green personality with positive plastic reduction attitudes. Highly conscientious individuals are more responsible for the environment, and are expected to strictly follow the plastic ban policies, whereas less conscientious individuals are more likely to turn a blind eye to them. More importantly, the relationship between a Conscientiousness personality and plastic reduction attitudes is negatively moderated by education. The discovery of education’s moderating role suggests that both an inborn personality trait of Conscientiousness and post-born education can complementarily shape residents’ plastic reduction attitudes. The findings of this study deepen the understanding of the causes of pro-environmental attitudes and provide valuable insights into plastic management in China.