Drawing on Appraisal theory within Systemic Functional Linguistics, this study employs a corpus-based approach to examine how EFL writers of high- and low-scoring argumentative essays use Engagement resources both individually and in combination to construct arguments within the argument chain at the paragraph level. The quantitative analysis reveals that while both groups use Contract Heterogloss more frequently to assert claims and conclusions, low-scoring writers heavily depend on Pronounce, whereas high-scoring writers utilize a diverse range of Contract Heterogloss. The qualitative analysis indicates that high-scoring writers develop and strengthen their assertive claims by presenting solid reasons and credible evidence to engage with potentially dissenting readers. These elements are incorporated into their writing through combinations of Engagement resources, such as Counter + Entertain/Deny/Justify and Endorse/Entertain + Entertain. However, low-scoring writers failed to adequately support their claims by skillfully deploying Engagement resources across different stages of argument, ultimately weakening the persuasiveness of their arguments. Our findings highlight the importance of providing students with instruction on Engagement strategies and their persuasive impact from a dialogic perspective. The identified strategies can therefore serve as pedagogical tools to assist students in constructing effective arguments by adeptly utilizing Engagement resources, facilitating interaction with external viewpoints and readers.