Sudden and unplanned purchasing behavior is considered impulsive buying behavior. With the increasing popularity of social commerce platforms and shopping automation, people's tendency towards impulsive purchases has grown significantly. In this connection, the role of marketing influencers has crucially impacted the customers' purchasing decisions over the last decade. This study aims to investigate the effect of marketing influencers on impulsive buying behavior. In addition, the current study addresses a critical methodological problem by highlighting the optimal configuration provided by fuzzy set qualitative comparative analysis (fsQCA) using a multi-criteria decision approach (MCDM). Based on a survey of 672 users of live streaming commerce platforms in Malaysia, we examined impulsive buying behavior from the perspective of influencer marketing, cognitive trust, and affective trust in influencer. Partial Least Squares Structural Equation Modeling (PLS-SEM) results confirmed the influence of parasocial relationship, authenticity, expertise, trustworthiness, attractiveness, and influencer–follower congruence on impulsive buying behavior through cognitive trust in influencer, affective trust in influencer, and behavioral inertia. The fsQCA results provided 15 different configurations confirming the role of marketing influencers' characteristics in impulsive buying behavior. However, fsQCA analysis is unable to determine the optimal solution or configuration. To this end, the MCDM analysis complemented the fsQCA analysis by unveiling the optimal configuration, which was the ninth configuration. Furthermore, the combination of authenticity, expertise, trustworthiness, cognitive trust, affective trust is considered a key concept to increase impulsive buying behaviour regardless of the presence of a parasocial relationship.