Emerging labour crises highlight the detrimental impact of overtime work cultures, such as the 996 working system, which violates the Labour Law of China and mirrors modern labour slavery. Simultaneously, despite China’s Three-Children Policy aimed at increasing national labour force growth, the national fertility rate has remained persistently low over the past decade. Workers require family time and financial security to plan for having children. Changes in family structures and fertility expectations, shaped by social pressures and the government’s advocacy, heavily impact labourers’ household financial behaviour. In response to a high-pressure overwork environment, labourers adopt conservative financial strategies to safeguard their families’ well-being and birth plans. This cautious approach often involves avoiding digital financial tools associated with riskier investments. This study examines the intersection of labour overwork, fertility, and the adoption of digital finance in shaping Chinese families’ investments. Drawing on the Theory of Planned Behaviour, this study analyses the panel data from 7,582 family observations in China between 2018 and 2020. The findings reveal that although digital finance positively influences household financial investment, the 996 work system acts as a moderator to shape this relationship negatively. Moreover, fertility in households further weakens this relationship. These findings provide critical theoretical insights into the dynamics of labour history by portraying a modern slavery picture of overworked labourers and their families in China: too exhausted and financially strained to have babies. It offers practical insights for policymakers aiming to improve labour policies, fertility rates, and household financial resilience.