Objective: This study aims to analyze the strategic role of influencer marketing in brand building and increasing MSME sales on Shopee and TikTok Shop. The focus of the research is directed at the relationship between influencer niche relevance, content quality, and micro-influencer efficiency on sales conversion.

Methodology: The research uses the Systematic Literature Review approach and narrative synthesis, by examining academic journals and the latest industry reports in Southeast Asia. This method is used to map empirical findings regarding the effectiveness of influencer-based digital promotion strategies.

Results: Findings show that influencer niche relevance has a significant effect on increasing brand engagement, supporting the Match-up Hypothesis. The quality and consistency of content, especially through short videos and live commerce sessions, increases sales conversions by strengthening the credibility of messages and triggering impulse purchases. In addition, micro and nano influencers have been proven to produce an average ROI 1.8 times higher than macro influencers, making them more efficient for MSMEs with limited budgets.

Conclusion: Influencer marketing based on niche relevance, quality content, and the use of live commerce is an effective strategy for MSMEs in increasing engagement and sales on e-commerce platforms. Micro-influencers are a more cost-efficient option.

Limitations: This study relied on secondary data from various publications so that the validity of the findings was influenced by variations in sales tracking methods in the original source. In addition, the focus of the research is limited to the two main platforms and the Indonesian context, so generalizations have limitations.

Contributions: This study provides an evidence-based framework for MSMEs in designing optimal influencer marketing strategies, including the selection of relevant influencers, content quality improvement, and the use of live commerce to maximize sales conversions.