Background/Objectives: Although the health benefits related to physical exercise for adolescents with cerebral palsy (CP) have been recognized, studies indicate that individuals with CP at school age are less involved in physical activities than their typical peers and are twice as likely to engage in sedentary behaviors. Therefore, our study aims to investigate the effects of a physical exercise program on physical fitness, stress, anxiety, and quality-of-life variables. Methods: A total of 15 teenagers with ambulatory CP (n = 8 boys, n = 7 girls, between 12 and 18 years old; M = 14.35; SD = 1.76) completed a 12-week program based on a mixed-method approach with face-to-face and live online activities. The outcome measures were physical fitness, stress, anxiety, and quality of life. Results: The 12-week exercise program resulted in gains in muscular strength, flexibility, and aerobic endurance tests, characterized by an increase in average walking speed and average VO2 max. There was also a significant change in the perception of emotional states of depression, anxiety, and stress reported by the participants. Conclusions: The program proved to be effective in physical fitness tests and perception of emotional states. Given the positive effects produced by the program, its design appears to meet the demands of adolescents with cerebral palsy.