Despite the global adoption of Content and Language Integrated Learning (CLIL) and extensive research on the effectiveness (product-oriented) and classroom interactions (process-oriented) of CLIL, existing studies have overlooked the motivational beliefs and metacognitive strategies of CLIL students. Hence, there is a need for a participant-oriented approach to better understand students' perspectives and enhance CLIL's success. Drawing on the social cognitive model of self-regulated learning (SRL), this study aimed to explore how students plan, monitor, and evaluate their learning in CLIL contexts by employing a novel vignette-based microanalytic assessment approach to empirically capture students' SRL processes. Participants were 108 junior secondary school students from three schools in Hong Kong. Data were analysed using structuring qualitative content analysis. Findings revealed that students employed diverse strategies to manage the demands of language and content learning, with variations in self-efficacy beliefs influencing their approaches. Furthermore, some learners faced challenges in maintaining effective self-regulation. This study argues that improving self-regulatory processes and enhancing CLIL's success requires prioritising assessment, considering the state of 'others', and fostering deeper learning beyond CLIL. This study contributes to the empirical, methodological, and pedagogical understanding of students' SRL in CLIL settings and informs future research on student-focused aspects in CLIL.