While automated feedback is becoming readily accessible to student writers, how students employ resources and strategies to use such feedback remains largely unexplored. Informed by activity theory and the construct of appropriation, this study conceptualizes students' use of automated feedback as social appropriation mediated by resources and internalization strategies. Based on multiple sources of data including students' drafts, automated feedback and submission information, semi-structured interviews and documents, this study explored a cohort of English as a Foreign Language (EFL) students' experiences of appropriating automated feedback in their writing activities. The findings revealed three forms of appropriation (i.e., regular, partial, and rare) among the students, who had used various artifacts (e.g., dictionary) and rules (e.g., teacher requirement), taken on different roles (e.g., student writer, spotlight-avoider), and resorted to different community members (e.g., peers) to mediate their appropriation. The findings also showed that the students further differed in their internalization of the resources through three sub-processes: selecting, emotion-regulating, and goal-setting. These findings pose a critical need to revisit the idea that submission for immediate automated feedback is motivating and to watch the potential washback effect of setting a threshold score when pedagogically using automated feedback. The study argues that students should develop their awareness of the mediating resources and the internationalization strategies for more self-regulated use of automated feedback.