Writing has been recognized as a core competency for postgraduate students. However, improving writing performance, particularly for first-year postgraduate students, remains an important and challenging task. This study aimed to explore the effects of student engagement in peer feedback on writing performance from cognitive, affective and behavioral perspectives. Specifically, the participants were 88 postgraduate students. With the support of an online writing and peer review system (Peerceptiv), participants were asked to write an essay, engage in the peer feedback process, and revise their essays. Correlation analysis and multiple regression analysis were utilized to analyze data on the quality of participants' essays, peer feedback procedures, and interviews. Results showed that cognitive engagement, affective engagement, and behavioral engagement were significantly associated with postgraduate students' writing performance. The analysis indicated that the helpfulness of provided comments was the strongest predictor of writing performance, followed by suggestion, integration, and positive affective engagement. These findings highlight the significance of student engagement in peer feedback to improve writing performance in higher education. Recommendations for future research on quality improvement in writing performance are suggested based on the findings.