The purpose of this research is to assess the consequences of voluntary self-disclosure in social media functioning as a consumer’s personality trait by examining user-generated content (UGC) perception – drawn from source credibility and attractiveness – and UGC behavior – drawn from consumer online brand-related activities (COBRAs). This study examines the extent to which self-disclosure favorably impacts perceived UGC trustworthiness and familiarity, and how this in turn affects subsequent brand attitude and purchase intention. This study further looks into how UGC behavior affects purchase intention. Using 301 valid responses, a confirmatory factor analysis (CFA) and structural equation modeling (SEM) are employed. The results indicate that consumers with a high level of self-disclosure not only generate trust and familiarity toward UGC but are also active in engaging in UGC behavior. The findings suggest that the more consumers create, consume, or contribute to UGC, the more they want to purchase the products and/or brands shown in UGC. Perceived UGC trustworthiness and familiarity, in turn, lead to positive brand attitudes and purchase intentions. Coincidently, this study confirms that self-disclosure begets positive UGC behavior using UGC perception as a mediator. This research provides practical insights into the mechanisms underlying UGC perception and UGC behavior, and it ultimately helps facilitate consumers’ self-disclosure to improve brand attitude and purchase intention.