Previous research has rarely considered the nested nature of family solidarity when investigating the within-group heterogeneity of parent-child solidarity, particularly within the context of Korean families. Consequently, less is known about patterns of intergenerational solidarity at the family level during the COVID-19 pandemic in South Korea. Using data from Korean parents with multiple adult children during the pandemic, this study aimed to identify heterogeneous patterns of parent-children solidarity both at the individual and the family levels. Furthermore, this study explored whether patterns of intergenerational solidarity with adult children at the family level were associated with parents’ psychological outcomes (depressive symptoms, self-esteem, and life satisfaction). A total of 515 parents and their 942 adult children were included in two-step Multilevel Latent Class Analyses and regression analyses. The results showed that there were five different parent-child solidarity classes at the individual level. At the family level, four intergenerational solidarity latent classes were identified: primarily tight-knit-traditional, primarily social-traditional, primarily social-and-digitally connected, and mixed. We found that parents with a primarily tight-knit traditional relationship with their adult children at the family level reported better psychological outcomes than those with a mixed relationship with their adult children. In addition, parents with a primarily social-and-digitally connected relationship with their adult children reported better life satisfaction than those with a mixed relationship with their adult children. Our findings suggest that considering the nestedness of children when examining parent-child solidarity patterns is important to understand better parent-child solidarity at the family level and its impact on psychological outcomes.