Self-regulated learning (SRL) is considered a critical competence for lifelong learning that requires explicit instruction and consistent practice, especially for college students. Despite the abundant intervention studies on the role of SRL in students' academic performance in the Western world, very little is known in China in English as a foreign language (EFL). To address this issue, the current study utilised a mixed-methods approach to investigating the effectiveness of self-regulated language learning intervention (devised using Zimmerman's cyclical phase model of SRL) on Chinese EFL learners. One hundred sophomores from two intact classes were recruited to either an experimental or a control group and evaluated at pre-, mid- and post-tests for motivation, strategic competence and English proficiency. After the post-test, 30 students were selected to accomplish follow-up semi-structured interviews. The quantitative results revealed a significant increase for the experimental group for the three assessed variables in comparison with the control at the post-test. In addition, the qualitative results were employed to explore the diverse differences between the high and low achievers and the perceived variances after the intervention, which provided comprehensive knowledge of the SRL foreign language acquisition. Meanwhile, the limitations and the theoretical and pedagogical implications were further discussed.