While researchers have shown notable interest in influencer marketing for promoting customer-brand relationships, its impact on customer equity and, in turn, purchase intention warrants further investigation. This study explores how influencers’ quantitative metrics—including the number of “likes,” “comments,” and “shares”—displayed on their content affect purchase intentions through perceived message authenticity and customer equity. The data were gathered from 432 Facebook customers and analyzed by partial least squares structural equation modeling (PLS-SEM). The findings revealed that the number of “likes,” “shares,” and “comments” directly influences perceived message authenticity and indirectly influences customer equity drivers (including value equity, brand equity, and relationship equity) through perceived message authenticity. Customer equity drivers significantly influence purchase intention and mediate the effect of perceived message authenticity on purchase intention. This study is one of the few that focuses on demonstrating the relationship process through which influencers’ interactive content shapes customer equity and purchase intention. It extends the influencer marketing literature by adding new empirical evidence regarding the significant role of influencer marketing in maintaining customer-brand relationships, which receives a wide interest from researchers, practitioners, and social media marketers.