This study underscores the necessity of assessing well‐being concerns in online environments through the lens of individual differences, going beyond simply addressing external vulnerabilities. It examines the relationships among dark personality traits, fear of missing out emotions, and social media addiction. The stability and identifiability of these traits are essential for formulating practical policies and interventions. Structural equation modeling reveals the varied influences of dark personality traits on social media addiction. Specifically, while Machiavellianism has a direct effect on SMA, its indirect influence through FoMO is not significant. Additionally, narcissism influences SMA both directly and indirectly, and psychopathy impacts SMA indirectly through FoMO. Based on these findings, we recommend that platforms and businesses adjust their algorithms and content strategies based on the personality‐driven mechanisms identified, to enhance consumer welfare and promote more effective management practices.