Individuals develop personal networks in a cumulative way over the life course, with early adulthood being a critical period with multiple transitions relating to family formation and entry into the labour market. Existing research on personal networks and the life course usually stresses the impact of single life transitions and events on the composition of personal networks. Contrastingly, this paper investigates the impact of whole work-family trajectories over a retrospective time period of 20 years corresponding to early adulthood (roughly 20 to 40 years old) on the composition of personal networks. Drawing on a Swiss sample of individuals born between 1970 and 1975, results revealed the critical impact of the family trajectories for the development of personal networks, and showed how the current diversity of personal networks is accounted for by trajectories deviating from the family developmental model.