In view of the persistence of health inequalities and declines in leisure-sport participation over the life course, several quantitative investigations have explored the links between participation and other leisure activities, which have their foundations in childhood and youth, as a means of understanding adults’ health behaviours. This paper presents new qualitative evidence to examine the largely under-explored relationship between leisure-sport participation and health within the context of educational transitions among a sample of 30–35-year-olds in north-west England. Drawing on semi-structured interviews conducted with 19 participants between July and August 2009, the paper illuminates the differential impact that gender and social class had on sports participation, and other health-related behaviours (e.g. drinking and smoking), among different groups of adults during the inherently transitional life-stage of youth. The findings suggest that while significant, the length of time spent in education and the differential educational experiences recalled by adults cannot adequately explain the observed differences in health and leisure-sport participation. The major sources of difference, while associated with educational transitions, appeared to lie instead in the broader inequalities that characterized adults’ lives and it is argued that simply enhancing leisure-sport participation and individual lifestyle change, as a means of health promotion, is a futile endeavour that does little to tackle the socio-economic structural determinants of health. We conclude by suggesting that until this is recognized by government and those both inside and outside of the health and sport policy communities, stubborn differences in leisure-sport participation rates and health inequalities—that have their foundations in childhood and youth, but extend over the life course—are likely to remain intact, and the unequal lives people currently lead are likely to become even more unequal in the future.