Digital content marketing that increases consumers’ favorable behavior is of increasing interest to marketers. However, there is a lack of studies that examine the relative effect of digital content marketing on brand defense. Building on the theoretical lens of elaboration likelihood model, attachment theory, and source credibility theory, this experimental study examines the relative effect of two types of digital content marketing on brand defense, taking into consideration the mediation effect of behavioral engagement and the moderation effect of age generation. Based on 237 participants collected from a United States sample, the findings of this study revealed that user-generated content is a stronger predictor of brand defense and behavioral engagement compared to firm-generated content. Further, behavioral engagement served as a mediator variable between the digital content marketing types and brand defense. Significant evidence has additionally been found between behavioral engagement and brand defense. Moreover, the findings of the moderation analysis illustrated that Generation Z is the most influenced by user-generated content, followed by Generations X and Y. Generation Y is the most influenced by firm-generated content, followed by Generations Z and X. This study adds empirical relevance to the growing literature of the importance of digital content marketing, behavioral engagement, and generation as well validates the effects of those constructs on brand defense.