The rapid evolution of digital media has transformed the marketing landscape, with influencer marketing emerging as a powerful tool for brand communication and consumer engagement. The study investigates how influencer credibility and perceived authenticity affect consumer trust and subsequently influence brand engagement in the digital era. Given the increasing role of social media influencers in shaping consumer perceptions, the research aims to uncover the psychological mechanisms driving consumer trust and behavioral outcomes, while also assessing the moderating role of disclosure transparency. A quantitative, cross-sectional research design was employed, using data collected from 412 social media users who follow influencers on platforms such as Instagram, YouTube, and TikTok. The study utilized a structured online questionnaire and analyzed the data using SPSS and SmartPLS, including reliability testing, confirmatory factor analysis, and Partial Least Squares Structural Equation Modeling (PLS-SEM). The results show that consumer trust is greatly influenced by perceived authenticity and influencer credibility, both of which are important predictors of brand engagement. The links between influencer qualities and engagement were shown to be mediated by trust. The effect of authenticity on trust was strengthened when disclosure transparency was high, highlighting the importance of clear communication in sponsored content. These results contribute to theoretical models in influencer marketing by validating and extending frameworks such as Source Credibility Theory and Parasocial Interaction Theory. Practically, the study underscores the importance of selecting credible and authentic influencers, encouraging transparent disclosure practices, and fostering trust-based consumer relationships. Future research should explore these dynamics longitudinally and in emerging areas such as virtual influencers and AI-driven marketing environments.