Large-scale online learning for university students is often plagued by challenges such as lack of learning motivation and autonomy. The achievement motivation theory emphasizes the individual’s motivation to pursue success and avoid failure. Based on the achievement motivation theory, this study aims to extend the research on understanding the relationship between learning motivation and self-regulated learning (SRL), including goal-setting, strategy use, self-regulation, and self-evaluation, by identifying possible mediators in this relationship. To achieve this, we survey 559 participants who are compelled to switch to home-based online learning (HBOL). Using structural equation modeling partial least squares (SEM-PLS) and Shapley value, we examine the effects of learning motivation, learning intention, and self-efficacy on SRL. Our findings reveal that learning motivation has both a direct and significant impact on SRL, as well as an indirect influence via self-efficacy and learning intention. These results underscore the importance of confidence and intention in successful online SRL for university students, and provide a foundation for further research in this area.