Social Media Influencers: A Systematic Review and Consolidated Definition

Social media influencers (SMIs) have emerged as powerful actors shaping brand awareness and consumer behavior. However, their impact is expanding beyond purely economic functions into areas such as politics, public health, and disaster communication. Existing literature tends to define the concept of SMIs rather narrowly, focusing either on their relevance within specific academic disciplines (e.g., marketing) or on categories of reach (e.g., micro, meso, and macro influencers). Narrow or inconsistent definitions and conceptualizations of SMIs across disciplines hinder theoretical development and limit comparability between studies. Therefore, this paper aims to establish a consolidated definition of SMIs. Using a seven-stage review methodology, we systematically derive a definition that captures the essential characteristics of SMIs, reflects their transformative role in societal discourse, and remains applicable to emerging artificial incarnations of the phenomenon.