In work-family research the effects on the individual, or the "self", in terms of personal interests independent of the work and family domains, have been largely neglected. This longitudinal study on 471 Japanese employees with young children investigated how job demands and job resources may have an impact on well-being by facilitating or hindering personal functioning. It was hypothesized that workload would have an unfavourable impact on work-to-self conflict, while supervisor support would have a favourable impact on work-to-self facilitation. In addition, we hypothesized that work–self conflict would diminish well-being (psychological distress and happiness), while work–self facilitation would enhance well-being over time. Structural equation modelling analyses using a full panel design showed that work overload was positively related to work–self conflict over time, whereas supervisor support was positively related to work–self facilitation. Furthermore, work–self conflict predicted psychological distress and happiness at T2, one year later, after controlling for T1 levels. These findings suggest that the demands and resources encountered at work can spill over to the home domain and have an impact on personal functioning and context-free well-being. Further research is needed to determine the importance of work-self constructs in relation to work-family constructs.