The purpose of this study was to examine the contribution of quality physical education (QPET) in a Comprehensive School Physical Activity Program (CSPAP) which is intended to promote physical activity (PA) behaviors in and outside of schools. Participants were nine elementary physical education teachers and their fourth- and fifth-grade students (n = 1111) in year one, n = 1012 in year 2). The student's daily PA minutes were assessed using a 7-day PA log. The PE teachers' levels of QPET were assessed by coding 63 videotaped lessons (M[subscript lessons/teacher] = 7.03, SD = 0.74) using the Assessing Quality Teaching rubrics (AQTR), which consisted of four essential dimensions including Task Design, Task Presentation, Class Management, and Instructional Response. Codes were confirmed through interrater reliability (82.4%, 84.5%, 94%). Data were analyzed through descriptive statistics, bivariate correlations, multiple R-squared regression models, and independent sample t tests. The results indicated that the overall QPET practices (R = 0.126, R[superscript 2] = 0.02, F = 32.387, Sig.= 0.000, P < 0.01) and all four essential dimensions (R = 0.127, R[superscript 2] = 0.02, F = 8.560, Sig.= 0.000, P < 0.01) were significant contributors to students' student daily PA behaviors. These predictors were significantly higher in girls (R = 0.157, R[superscript 2] = 0.03, F = 6.15, Sig.= 0.000, P < 0.01) than boys (R = 0.113, R[superscript 2] = 0.01, F = 3.57, Sig.= 0.007, P < 0.01). The Instructional Response was a significant predictor of PA among girls (ß = 0.12, t = 2,068, Sig. = 0.039, P < 0.05 level), but not boys. Further, students' who experienced high QPET were significantly more physically active than those students who did not have this experience (t = 4.334, df = 2089, Sig. = 0.000, P < 0.01). It was concluded that the QPET practices played a critical role in promoting students' daily PA engagement in and outside of schools.