When Social Media Influencers Work: A Meta‐Analysis of Brand Engagement, Behavioral Intention, and Boundary Conditions

ABSTRACT This study examines how social media influencers (SMIs) shape brand engagement and behavioral intention and when these effects vary across contexts. Drawing on 97 studies with a sample of 40,330 participants, we employ one‐stage meta‐analytic structural equation modeling (OSMASEM) to estimate the effects of SMI credibility (attractiveness, expertise, and trustworthiness) on brand engagement and behavioral intention. The results reveal a division of persuasive labor. Attractiveness is the only credibility attribute with a significant direct effect on brand engagement, whereas expertise exerts the strongest direct effect on behavioral intention, with trustworthiness and attractiveness also significant. Brand engagement predicts behavioral intention, but the indirect effects of SMI credibility through brand engagement do not reach significance. Cultural, economic, contextual, and parasocial moderators showed limited evidence of path‐specific moderation. These findings provide evidence‐based guidance for matching influencer traits to campaign objectives across markets and platforms.