STEAM education has been widely promoted to foster interdisciplinary learning, creativity, and problem-solving skills. However, the integration of Physical Education (PE) within STEAM frameworks remains underexplored, particularly in Primary Education. This study examines the impact of a STEAM-based intervention incorporating Physical Education on motor competence, academic achievement, and creative problem solving among primary school students. A quasi-experimental design with pre- and post-test measures was implemented in two public primary schools. The sample comprised 124 students (aged 9–11 years). The experimental group participated in a 12-week interdisciplinary STEAM program integrating science, mathematics, engineering design, arts, and physically active learning tasks embedded in PE sessions. The control group followed the standard curriculum. Motor competence was assessed using standardized movement skill tests, academic achievement through mathematics and science performance tasks, and creativity through validated divergent thinking measures. Data were analyzed using mixed ANOVA and effect size calculations. Students in the experimental group demonstrated significant improvements in motor competence (p < .01), mathematics and science achievement (p < .05), and creative problem solving (p < .01) compared to the control group. Effect sizes ranged from moderate to large (η² = .08–.21). Integrating Physical Education within a STEAM framework in Primary Education enhances not only motor development but also academic and creative outcomes. These findings support interdisciplinary models that position physically active learning as a catalyst for holistic educational development.