BackgroundThe coronavirus 2019 (COVID-19) pandemic has negatively altered many families’ lifestyles and the mental well-being of parents, especially those who have a low income and young children. To improve low-income parents’ mental well-being, especially during a pandemic, understanding parents’ and children’s lifestyle behaviors and the relationship between their lifestyle behaviors and parents’ mental well-being is essential.ObjectiveThis cross-sectional study examined relationships between lifestyle behaviors (sleep, physical activity, screen time, and eating behavior of parents and children) and low-income parents’ well-being (stress, anxiety, and depression) during COVID-19.MethodsParents were recruited from two Michigan Head Start organizations as well as across the United States; 408 parents completed an online survey. Demographic characteristics were assessed, along with parents’ sleep, physical activity, screen time, and dietary intake; stress, anxiety, and depression were also examined. Children’s sleep time, physical activity, screen time, and fruit/vegetable intake were assessed. Descriptive statistics, correlations, and the multivariate general linear model procedure were used.ResultsApproximately 69.4% of parents reported moderate stress levels, and 17.2% reported high levels. Most parents had sleep disturbances, attained minimal physical activity, and consumed <5 fruits/vegetables per day; average screen time was >2 hours per day. Only 41% of preschoolers were active 7 days a week and slept ≥10 hours per day. Two thirds had >2 hours per day of screen time, and less than one fifth consumed ≥5 fruits/vegetables per day. After adjusting for parents’ demographics and children’s lifestyle behaviors, parents’ sleep disturbance was positively correlated with their levels of stress, anxiety, and depression. After controlling for parents’ demographics and lifestyle behaviors, child sleep time was negatively associated with parents’ stress levels. Family demographics and parents’ and children’s lifestyle behaviors explained 33.4%, 29.8%, and 28.1% of the variances in parents’ stress, anxiety, and depression, respectively.DiscussionMost parents and preschoolers were not meeting many lifestyle behavior recommendations, indicating a need for interventions. Improving parents’ sleep quality and reducing bedtime challenges involving their preschoolers may be necessary for enhancing parental mental well-being.