Purpose Environment is an independent factor affecting quality of life. Studies suggest that health practices consider having an impact on quality of life. The purpose of the present paper was to examine the association between environmental conditions and quality of life, and how individual health practices affected this association. Methods Participants aged 20 or above were recruited from 11 tertiary planning units in the centre of Kowloon. These tertiary planning units were selected as they represent the overall living environment in Hong Kong, with older poorer urban areas alongside relatively affluent districts. A mediation analysis was implemented using multiple linear regressions to examine the effects of environmental conditions on quality of life. The predictor variables included sociodemographic and environmental conditions, health practices and health service utilisation. Results Of the eligible 607 participants, 390 females and 217 males with a mean age of 47.4 were included for analysis. Physical, psychological and environmental factors were conducive and connected to quality of life. After adjusting for fruit and vegetable intake, gender, education level and chronic illness, perceived stress and sleep quality had significant mediating effects. Conclusion Environment is an important factor that affects the overall well-being of individuals. The interaction of environmental quality with individual variables, specifically stress and sleep is extremely important when assessing its impact on the quality of life. The findings of this study support the importance of individual stress and sleep in mediating the relationship between the environment and quality of life.