• family life course theory;
  • work–family spillover;
  • work, family stress

Work–family research employing nationally representative samples and multiple methods of data collection is uncommon. We used data from two affiliated national surveys to examine the distribution of work–family spillover among working adults. The National Study of Daily Experiences (n= 741), an 8-day daily diary study using a subsample of the National Survey of Midlife Development in the United States (MIDUS; N= 2,130), allowed work–family spillover to be conceptualized and operationalized in different ways. Analyses testing family life course hypotheses indicated that self-reported negative and positive spillover between work and family were not randomly distributed within the labor force. Age was found to have a persistent curvilinear effect on negative spillover between work and family. The prevalence of co-occurring work and family stress reported over 8 days was comparable across nearly all the sociodemographic characteristics.