A study evaluated the implementation of the Whole School, Whole Community, Whole Child (WSCC) model in public elementary schools in Makkah, Saudi Arabia, and its effects on students’ body mass index (BMI) and academic performance. Conducted in 2022, the cross-sectional study involved 385 students and 32 school staff from both health-promoting schools (HPSs) and non-HPSs. Researchers assessed four WSCC domains: community involvement, family engagement, physical environment, and counseling services, using validated questionnaires. Results showed that students in HPSs had higher WSCC implementation and academic achievement, with a median academic score of 687 compared to 665 for non-HPS students. WSCC implementation was identified as an independent predictor of academic success, while its link to BMI was not significant. The study also found a dual burden of underweight and overweight among students. To improve learning and well-being, the study suggests enhancing WSCC implementation, focusing on mental health support, family and community engagement, and equitable policy adoption.