<p>Affect balance holds paramount significance in fostering physical and psychological well-being, as well as the long-term growth of children and adolescents. Whether and how meeting 24-hour movement guidelines (24-HMG) relates to affect balance remains unclear. This study aims to investigate the relationship between meeting 24-HMG and affect balance, and to explore the potential mediating mechanisms underlying this relationship. A sample of 530 Chinese children and adolescents (mean age: 12.95 years; 49.81% males) participated in this study and completed measures of 24-hour movement behaviors, affect balance, executive function, and cognitive reappraisal. The results showed that meeting 24-HMG was positively associated with affect balance. Notably, executive function emerged as a mediating factor between meeting 24-HMG and affect balance. Furthermore, executive function and cognitive reappraisal exhibited sequential mediating effects in this relationship. The current study underscores the importance of adhering to 24-HMG in promoting affect balance among children and adolescents. Moreover, it highlights the pivotal role of executive function and cognitive reappraisal as sequential mediators. Practical implications suggest implementing strategies to encourage compliance with 24-HMG to maintain optimal affect balance in this population.</p>