This study aimed to evaluate the effectiveness of physically active breaks of a total duration of 10 min a day, introduced during curricular lessons, together with a 10 min physical activity intervention during the daily school recess period on obesity prevention, fitness, cognitive function, and psychological well-being in school-aged children. A sample of 310 children (139 boys vs. 171 girls), aged between 8 and 10 years (9.82 ± 0.51), was selected. Our strategy was implemented over a 6-month period and the participants were randomly assigned to either the intervention group (n = 157) or the non-intervention (control) group (n =153). In the intervention group, a significant decrease (p < 0.05) in body mass index, waist circumference, waist–height ratio, and relative body fat mass was achieved after the intervention (T1) compared to the values measured before intervention (T0); in the control group, no differences emerged between T0 and T1 for any of the parameters considered. We found a significant increase in the intervention group in standing long jump, Ruffier, and sit and reach test scores (p < 0.001 for all). At T0, cognitive test scores did not differ between the girls and boys or between the intervention and control groups; instead at T1, significant differences were observed in the two groups regarding the total number of responses and the concentration performance scores (p < 0.001). Consistently, in the intervention group, well-being levels significantly increased between T0 and T1 (p < 0.001). Finally, the intervention had significant effects on the children regardless of gender. We may therefore conclude that schools should create more opportunities for teachers and students to introduce intervention strategies to promote regular PA during school recess.