This research examines underdog brand biographies— narratives on brands’ passion and determination leading to success despite the lack of resources (Paharia et al., 2011)—and shows positive effects of underdog biographies when the brand is the source of the narrative, but not when an independent third-party is the source of the narrative. Further, this research finds evidence for a mediating role of narrative transportation: Exposed to an underdog brand biography from a brand source, consumers are carried away by the narrative and experience narrative persuasion, resulting in higher purchase intentions. Theoretical and practical implications of these findings are discussed.