This study investigated the effect of product messages through one-person media, the growing media with great marketing potential, by conducting an experiment in which the perceived expertise of the influencer and the perceived commerciality of the message were manipulated. The results showed that when the perceived expertise of the influencer is high, the product message through one-person media generates a positive behavioural intention and attitude toward the message. The perceived commerciality, in contrast, was found to have an insignificant influence on persuasion effect. The interaction effect between the two independent variables was found to be significant. Based on the results of analysis, this study derives theoretical and practical implications for one-person media communication contexts, and suggests a direction for follow-up research.