Like many nations, population ageing is challenging Australia’s economic future; increasing the workforce participation of mothers and mature-aged adults are two policy strategies to address it. Drawing on a Health in All Policies (HiAPs) framework, our study aims to supply longitudinal evidence on connections between this policy strategy and health. Considering physical inactivity, poor mental health, overweight and obesity we estimate associations with the level of participation (not employed compared with part- or full-time employed). Using eight waves of data from the Household, Income and Labour Dynamics in Australia survey, a series of random intercept logistic models estimate the odds for mothers (n = 2105) and Australians aged 55–64 years (n = 3201) on each health outcome. We find that there are health benefits as well as risks linked to level of participation. Mothers who worked >20 h/wk had higher odds of physical inactivity, as did mature-aged Australians working either part - or full-time. Working part- or full-time was unrelated to overweight or obesity over the span of our study. Level of participation was unrelated to mental health among mature-age Australians, although part-time (but not full-time) work benefited mothers’. In terms of health, working more may offer mixed blessings to these two target populations; part-time work appears to be optimal. By using health as a metric, our study adds to the case for a HiAPs approach.