Recent studies identify Self-Regulated Learning (SRL) as a key factor in enhancing cognitive development, particularly within Computational Thinking (CT) literature. However, research gaps remain in understanding how SRL and CT interact from a developmental perspective. Our study designed a program with tailored animations and worksheets to specifically foster students' learning and cognitive development. Using a mixed-methods approach, we administered surveys among 1235 students from 29 Hong Kong primary schools to investigate a dynamic learning system comprising SRL and CT in a large-scale CT program. Additionally, semi-structured interviews were conducted with 15 students to further probe insights. Quantitative findings revealed a mutually reinforcing relationship in the dynamic system, suggesting that higher SRL skills enhance cognitive CT abilities, and vice versa. Complementing these results, qualitative findings showed that integrating animations and worksheets into the CT program significantly boosted students' SRL and cognitive development. These findings have significant implications for educational practices and curriculum design. Schools should consider implementing SRL strategies, such as proactive goal setting and reflective evaluation, within their curricula to promote students’ cognitive development. Furthermore, strategic investments in educational technology, including collaborations with EdTech developers, are essential to create effective, pedagogically sound tools that enhance learning outcomes. These insights provide valuable guidance for creating a supportive SRL environment that fosters cognitive development in primary school education. Copyright © 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.