This study aimed to explain the role of the physical classroom environment and flexible design in enhancing learning and creativity among lower elementary school students based on Gibson’s Affordance Theory. This study used a mixed-methods quantitative–qualitative approach with a concurrent exploratory design. The statistical population included first-grade elementary students, teachers, and parents in Sari during the 2024–2025 academic year. In the quantitative phase, 120 participants were selected through simple random sampling. Data were collected using a researcher-made questionnaire. The reliability of the instrument was confirmed with a Cronbach’s alpha coefficient of 0.869. Data were analyzed using Structural Equation Modeling in SmartPLS 3.3. The results indicated that the proposed model had satisfactory explanatory power. The coefficient of determination was 0.724 for learning and 0.689 for creativity. Activity-based design had a positive and significant effect on learning (β = 0.473, p < 0.001). Flexible design showed the strongest direct effect on creativity (β = 0.706, p < 0.001). Learning also had a positive and significant effect on creativity (β = 0.469, p < 0.001). The direct effect of activity-based design on creativity was not significant, whereas its indirect effect through learning was confirmed (β = 0.222, p < 0.001). The findings show that physical flexibility, activity-based organization, and functional diversity in classrooms can enhance students’ active learning and creativity by providing opportunities for action, interaction, movement, and experience. Therefore, revising elementary school design standards based on flexible and human-centered learning environments is essential.