Despite a surge of research interest in feedback engagement in higher education, postgraduate students' engagement with multiple sources of feedback in the context of academic writing is understudied. Informed by the notion of feedback literacy, we explore how Chinese postgraduate students perceive and engage with automated, peer and teacher feedback, as well as the feedback process as a whole, in academic writing. The analysis of 120 students' diaries and ten students' interviews shows that multiple sources of feedback and related activities complement each other in feedback areas (e.g. grammar, content, structure), perspectives (e.g. reader, expert) and depth of improvement to the writing (e.g. from correction to polishing or refinement). We conclude that engaging with multiple sources of feedback supports students' writing and learning. This study adds to the literature by revealing the social, co-constructed, complementary and enabling nature of feedback engagement. The students engage with multiple sources of feedback and related activities internally, externally, proactively, critically and collaboratively in the intrapersonal, interpersonal and human-material spheres.