Although an underdog brand positioning can elicit positive consumer responses, maintaining a brand's positioning requires maintaining consistent brand associations. If the associations created by the company's service providers do not align with the brand's positioning, this discrepancy can lead to consumer confusion or to a decline in brand attitudes. Chatbots, as customer‐facing representatives, play a crucial role in how consumers perceive and evaluate a brand. However, the role of chatbots in shaping brand attitude has not been extensively studied. Therefore, this study investigates the effects of chatbot conversational styles on consumers' perceptions of the fit between a brand's positioning and its messaging, focusing on both “top‐dog” and “underdog” brands. This study demonstrates that underdog brands using chatbots with warm conversational styles and top‐dog brands using chatbots with competent (i.e., professional) conversational styles foster positive brand evaluations by consumers through perceived fit. Additionally, this study introduces the concept of power state—an individual's degree of perceived control over their surroundings—as a moderator in human–chatbot interactions, demonstrating that high‐power‐state consumers of top‐dog brands favor a competent conversational style, whereas low‐power‐state consumers favor a warm conversational style regardless of the brand's positioning.