In 2021, China issued the "Double Reduction" (DR) policy to reduce the within- and outside-school burden on students. The policy requires all compulsory education schools to provide after-school services such as homework tutoring and well-rounded development activities for willing students. Based on student survey data from 13 schools in Wuhan city (N = 2,728), this study is the first to test the effects of after-school program participation on students' noncognitive outcomes after China's DR policy was implemented. Regression, logit, ordered logit, and propensity score matching models showed consistent effects for greater conscientiousness, calmness, focus, and confidence in the future. These effects mainly resulted from the extended activities that were not offered in traditional courses. Both positive and negative effects were found for homework tutoring program attendance. Some positive effects were greater for low-income students, girls, and students with poorer health, lower academic achievement, and rural household registrations.