The increase in social media use has raised concerns about its potential effects on users' subjective well-being, and researchers have extensively studied this topic. However, most studies are correlational, and the primary goal of this study is to examine whether social media exposure influences individuals' well-being using an experimental design. We hypothesized that exposure to academic achievement-oriented social media content (academic achievement vs. running achievement) would reduce positive emotions and life satisfaction while increasing negative emotions through malicious and benign envy. Additionally, the relevance of academic performance to self-definition is expected to moderate this indirect effect. Specifically, exposure to academic achievement-oriented social media content will increase negative emotions and decrease positive emotions and life satisfaction through malicious and benign envy, but only for participants whose self-definition is related to academic achievement. To test this, we conducted an experimental study using the Qualtrics platform. 326 participants (279 Female, 45 Male, and two did not report) first completed the Demographic Information Form and the Relevance of Academic Performance to Self-Definition Scale. They were then randomly assigned to one of two experimental conditions (an Academic achievement-oriented social media post vs. a running achievement-oriented social media post). They completed the PaDe State Malicious and Benign Envy Scale, the Positive and Negative Affect Schedule (PANAS), and the Satisfaction with Life Scale. Results showed that exposure to academic achievement-focused social media posts decreased positive emotions by lowering benign envy. Namely, academic achievement-oriented social media posts decreased benign envy, and as benign envy decreased, positive affect decreased as well. Also, malicious envy predicted negative emotions negatively and life satisfaction negatively, but the mediation effect was not significant. Also, the relevance of academic achievement to self-definition did not moderate either indirect effect. The findings are discussed in the context of how social media use impacts subjective well-being.