Background: Home-visiting programs often aim to improve parenting skills, parent-child relationships, and children's developmental outcomes for at-risk families. Although research has identified what elements of these interventions are effective when provided by professionals, little is known about effective components of volunteer-based home-visiting programs. Objective: This study focused on Home-Start, a preventive home-visiting program, delivering informal social support through volunteers to families with children up to 17 years old struggling with common parenting issues. The aim was to develop a detailed understanding of the core components of the Home-Start and thereby develop a better understanding of the unique elements of volunteer-based home-visiting programs. Methods: We interviewed 10 parents and 11 volunteers and used thematic analysis. Results: We found evidence for the relevance of the four principles identified by Home-Start the Netherlands. These are: Needs-oriented care, Focusing on empowerment, Equality and trust, and the Gift of time. We also describe a fifth theme, namely Professional support for the volunteer. The findings suggest overlap with effective components for professional-based support, but also highlight unique elements of volunteer-based home-visiting programs, which are rooted in the shared parenting experiences of volunteers and parents. Conclusions: This paper provides new insights into the unique value of volunteer-based support for families.