This study aimed to evaluate the role of digital marketing in the sustainable performance of micro, small, and medium-sized firms (MSMEs) in Indonesia by analyzing the relationship between digital marketing, buy intention, and actual purchase decision. A sample of 400 micro, small, and medium-sized firms (MSMEs) was chosen via a three-month-long online survey distributed via online platforms and social media. The poll, which was self-administered, queried about digital marketing techniques, purchase intent, and actual purchase decisions. The acquired data were analyzed using structural equation modeling (SEM) to determine the role of buy intent as a mediator between digital marketing and actual purchase decisions. The study's outcomes give solid evidence of a large positive association between digital marketing and MSMEs' buy intention and actual purchase decision, with purchase intention as a moderator. This supports the theory of planned behavior in addressing the relationship between digital marketing, buy intent, and actual purchase decisions. The findings of this study offer fresh light on the influence of digital marketing on MSMEs in Indonesia, stressing the importance of digital marketing in boosting the sustainable performance of MSMEs in Indonesia. These results can teach MSMEs and policymakers how to effectively adopt digital marketing strategies to improve the sustainable performance of MSMEs in Indonesia. The study also establishes the framework for future research into the relationship between digital marketing, buy intention, and actual purchase decisions in various contexts and industries.