Amid intensified educational reforms in China, secondary school PE teachers face rising workloads and stress, affecting teaching effectiveness. This study investigated stress management factors, performance effectiveness, and their relationship among 474 secondary school PE teachers in Changsha using a mixed-methods design. The increasing attention to stress management in education has highlighted its impact on teacher performance effectiveness, especially for physical education teachers in high-stress contexts. Quantitative analysis showed a moderate overall stress management level (M = 3.43/5), with strengths in cognitive evaluation (M = 3.58) and emotional state stability (M = 3.47), but lower scores in plan implementation (M = 3.33) and problem identification (M = 3.41). Regression analysis identified cognitive evaluation (β = 0.27, p < 0.001) and plan implementation (β = 0.18, p < 0.001) as significant predictors, explaining 63% of the variance in performance effectiveness. The integration of stress management into professional development and school policies can create a supportive culture that enhances teacher effectiveness and student outcomes. Qualitative interviews highlighted challenges such as heavy administrative workloads, limited institutional support, and variability in emotional regulation skills, indicating the need for targeted support. The study recommends localized stress management systems, continuous professional development focusing on practical stress management and emotional regulation, and performance evaluation frameworks incorporating stress management indicators. These measures align with China’s education modernization policies, aiming to integrate stress management into efforts to enhance PE teaching effectiveness and teacher well-being in Changsha’s secondary schools.