Students' mental health is an alarming issue in Hong Kong, thereby increasing concern from psychologists, who attempted to implement positive education programs to equip students with skills to counteract mental health problems. This study followed the practice from positive psychology and conducted a Flourishing Life program based on the framework of the PERMA model in a secondary setting. The aims of the present paper are two-fold: to report the effort of the program and to evaluate the program's effectiveness. A mixed-method sequential explanatory research design, including survey (n = 495) and subsequent two focus-group interviews (n = 8), was adopted to assess the program's effectiveness. Results indicated that Forms Two and Three students (Grades 8 and 9) benefited more from the program than the Form One students (Grade 7). Overall, students reported that they had benefited from the program. Findings provide supporting evidence to the whole-school approach program that operated effectively within the existing curriculum. This research may provide a direction for school curriculum leaders to promote students' well-being by infusing essence from positive psychology to the school curriculum.