Abstract: Since the State Council implemented the Air Quality Improvement Action Plan in 2013, China’s overall air quality has significantly improved. However, ozone (O₃) pollution has become increasingly prominent. Therefore, disentangling the impacts of meteorological conditions and emissions and evaluating the effectiveness of emission reduction measures are crucial for formulating precise prevention and control policies in Hangzhou. This study considers observational data from 15 monitoring stations in Hangzhou during the warm season from 2014 to 2023, comprehensively analyzes the evolution of multiple O₃-related indicators, and adopts a de-meteorologization method based on the random forest algorithm to quantify the respective contributions of meteorological conditions and emissions to long-term O₃, thereby assessing the effect of O₃ pollution control. The results show that the annual growth rates of MDA8 O₃ and O_x in Hangzhou as a whole are 1.4 μg m⁻³ a⁻¹ and 0.07μg m⁻³ a⁻¹, respectively. Both the rate of increase and the concentration levels are significantly higher in urban areas than in rural areas. The urban–rural gap in O₃ and O_x has widened over time, and reductions in NO_x emissions have not effectively suppressed the rise of O₃. Since 2018, meteorological conditions have changed from being unfavorable to favorable for O₃ generation, and this change has been most significant in May and September—the months with the most severe pollution. Generally, 64% of the overall interannual upward trend in O₃ pollution is caused by meteorological conditions, and the rest is due to ineffective management and control. When meteorological effects are removed, long-term management measures effectively reduce atmospheric oxidation capacity in both urban and rural areas and curb the rise in O₃ concentration in rural areas. However, these measures have had limited effect on O₃ levels in urban areas or on local photochemical production. The above results indicate that strengthening anthropogenic control measures under unfavorable meteorological conditions (especially in May and September) is key to suppressing O₃ pollution in Hangzhou.