Research has shown that the effectiveness of written corrective feedback (WCF) on writing performance depends on learners' engagement with WCF and its associated motivational state. However, little research has examined the inner causal relationships between motivation, learner engagement with WCF, and writing performance. The current study fills the void in the existing literature by taking a structural equation modeling approach as the methodological framework. Two independent Chinese undergraduate samples partook in the pilot and formal phases of the study. The results showed that cultivation of an ideal self-image significantly promoted both intrinsic and extrinsic motivations and enhanced learners' engagement with WCF, but ought-to self-image was found to have no such effects. Furthermore, both intrinsic motivation and learner engagement with WCF could directly influence writing scores, with the latter being more explanatory than the former. The implications of the research findings are provided and discussed.