Social involvement of enterprises, i.e., sharing wealth with those in need, can be spoken of only in the case of owner-managed family firms (FB). These companies account for two-thirds of all enterprises in the global economy; they contribute to the stability, development, and continuity of the existence of the economies of many countries. However, the sustainability of the existence of individual FBs is often threatened. Social engagement of owners and preparation of successors are the appropriate retort as they affect the transgenerational sustainability of these enterprises. The purpose of this study is to identify the causes, scope, forms, and beneficiaries of social engagement of Polish FBs. The study uses the Delphi method implemented in three stages: (1) selection of experts; (2) collection of information; and (3) development and interpretation of research results in the context of adopted research questions, research objective, and research hypothesis. The results of the study confirm that FBs make an important contribution to sustainable social development at the micro level. The social engagement of FBs brings benefits to both beneficiaries and donors, responds to genuinely existing needs, and supports the cross-generational sustainability of companies.