PurposeThis study aims to investigate the relationship between Internet celebrity characteristics and the follower's impulse purchase behavior in YouTuber. Attachment and parasocial interaction are mediating variables concerning the impact of Internet celebrity characteristics on followers' impulse purchase behavior.Design/methodology/approachThis study conducted an online survey of YouTube users in Taiwan and utilized quota sampling with 500 samples to examine the influence of two types of Internet celebrities on impulse purchase behavior.FindingsAs to the empirical results, the main path indicated that the self-disclosure Internet celebrity positively affected the attachment, which mainly positively affected the impulse purchase behavior. The second path showed that the expertise-knowledge Internet celebrity positively affected the attachment, which positively affected the impulse purchase behavior.Practical implicationsYouTube marketers should proceed prudently with the market segmentation and choose the appropriate type of Internet celebrities who are suitable for the product image to differentiate marketing. Empirical results can aid marketers in selecting a product-endorser, and enhance consumers' purchasing effect on product advertisements in interactive marketing.Originality/valueThe novelty of this study is to explore the mediation effect of the impact of Internet celebrity characteristics on followers' impulse purchase behavior in interactive marketing. The explaining mechanism of attachment and parasocial interaction is promised to be highlighted as the contribution of this study to the extant literature. This study constructs a theoretical mechanism between attachment theory and parasocial interaction theory and then can be used as a theoretical lens for designing successful social media strategies and explaining social media brand relationships.