Grounded in the activity theory, we adopted a sequential explanatory mixed-methods approach to explore the impact of automated written corrective feedback (AWCF) on English as a foreign language (EFL) learners' academic writing skills (i.e. task achievement, coherence and cohesion, lexicon, and grammatical range and accuracy). To this end, two intact classes were selected and randomly assigned to an electronic class (30 EFL learners), receiving AWCF electronically, and a non-electronic class (26 EFL learners), receiving written corrective feedback (WCF) non-electronically. Both groups of learners engaged in interactive writing activities guided by the principles of the activity theory, which capitalised on the roles of writing collaboration, social environment, and the mediation of electronic/nonelectronic artefacts to develop the writing skills. The required quantitative and qualitative data were collected via IELTS academic writing Task 1 and Task 2, a stimulated recall technique, and an individual semi-structured interview. The results of one-way ANCOVA indicated that the electronic learners outperformed their non-electronic counterparts in writing performance, task achievement, and grammatical range and accuracy, whilst no significant differences were found between the two groups' coherence and cohesion and lexicon. The stimulated recall technique, conducted with seven electronic EFL learners, confirmed the electronic learners' behavioural, cognitive, and affective engagement with the AWCF. The individual semi-structured interview, conducted with the same electronic learners, also indicated the electronic learners' positive and negative attitudes and perceptions towards the AWCF, further corroborating the findings. Pedagogical implications are discussed within the framework of the activity theory to clarify how instructional procedures and learning environments can be designed to more effectively contribute to EFL learners' interactive writing activities and, hence, their writing skills development.