This study aims to investigate the effects of AI disclosure (present vs. absent) and brand campaign message (value-oriented vs. standard) on consumer responses and the underlying mechanisms of those responses. To this end, the study examines how AI disclosure and brand campaign message influence consumer responses, focusing on the serial mediation of perceived campaign value, brand integrity, and consumer–brand identification. An online experiment with 156 adults was conducted. Results from a moderated serial mediation analysis revealed that, in value-oriented brand campaigns, AI disclosure led to significantly lower purchase intentions by reducing the perceived value of the campaign, which in turn lowered brand integrity and consumer–brand identification. However, these mediating effects were not observed in standard brand campaigns. These findings highlight the underlying psychological mechanisms behind the effects of AI disclosure on consumer responses and offer practical implications for the strategic use of AI in brand campaigns, tailored to the specific objectives of the campaign.