Well-being development in young people's formative years is crucial for their transition to adulthood. While research on well-being in formal education contexts is expanding, little attention has been paid to out-of-school educational settings, particularly supplementary tutoring for disadvantaged students. Adopting Sirgy's concept of positive balance, this paper examines the well-being of financially disadvantaged adolescents receiving fee-free one-on-one supplementary tutoring. A year-long longitudinal narrative inquiry was conducted with 18 adolescents on their English learning motivation in Hong Kong. Three rounds of individual interviews with each adolescent, their English writing and reflective drawing were analysed. Interviews with their parents and tutors were conducted, and tutorials were observed where possible. This paper focuses on three adolescents with different personal attributes and life circumstances, examining their strategies inspired by their tutoring experience to uphold well-being amidst educational and other challenges. This study demonstrates the potentials of informal educational environments in promoting students' well-being.