The primary goal of this research is to provide the social and psychological motivational factors that lead consumers to engage with commercial brands on SNS. Specifically, this study addresses consumers' motivations in terms of why they follow a brand's account on Instagram, helping us to understand what specific motives and needs consumers have regarding their use of the Instagram platform. Within the theoretical framework of U&G, this study found that individuals who follow Instagram brand accounts have seven social and psychological motives: "Social Interaction, Brand Love, Affinity for Instagram, Brand Admiration, Entertainment, Decision Making, And Information" that lead consumers to engage with commercial brands on Instagram. To further investigate the relationship between identified motives and consumer involvement in SNS brand accounts, Study 2 measured involvement outcome variables such as eWOM frequency, attitude toward brand, brand trust, brand satisfaction, pass along intention, and willingness to buy. The overall findings of this research point to the importance of applying social presence theory to understanding consumer behavior in the Instagram context. Brand account followers' intrinsic motivations may reduce the psychological distance that they perceive between themselves and the brand they are following.