Trolling is a pervasive form of online aggression, often rooted in adverse personality traits and amplified by the disinhibiting affordances of social media. The current study applies the I3 aggression model to examine the role of Dark Triad (DT) traits as impelling factors that increase trolling propensity, and Trait Emotional Intelligence (TEI) as an inhibiting factor that could constrain such behavior. The study also investigates whether TEI buffers the impact of DT traits on trolling and whether age further moderates this moderating effect. A total of 427 adult social media users (Mage = 22.71 years, SD = 3.71) participated in the study. Correlation analysis indicated that all three DT traits were positively correlated with trolling propensity, whereas TEI showed a negative association. Hierarchical regressions demonstrated that all three DT traits uniquely and positively predicted trolling. Machiavellianism and narcissism emerged as robust predictors even after accounting for shared variance with more callous traits such as psychopathy. TEI remained a significant negative predictor, and higher TEI levels attenuated the influence of each DT trait on trolling. Three-way interactions further suggested that the protective role of TEI in the relationship between psychopathy and trolling became stronger with age. Still, this pattern did not generalize to Machiavellianism or narcissism. Although three-way interactions were modest and inconsistent across traits, they underscore a concerning developmental trend as trolling appears to be most pronounced when dark traits surface during the emotionally formative period of emerging adulthood.