This study examines the relationship between volunteer work and six aspects of personal well-being: happiness, life satisfaction, self-esteem, sense of control over life, physical health, and depression, using data from the Americans' Changing Lives panel study (N = 2,681). The authors argue that previous research has often overlooked the antecedents of human agency, focusing instead on the consequences of volunteer work. They find that volunteer work enhances all six aspects of well-being, and that individuals with greater well-being invest more hours in volunteer service. The study also explores the reciprocal effects of personal well-being and volunteer work, suggesting a positive cycle of selection and social causation processes. The results highlight the importance of both individual characteristics and social integration in shaping the relationship between volunteer work and well-being. The authors conclude by discussing the implications of their findings for understanding the mechanisms through which volunteer work contributes to well-being and the role of self-selection versus social selection in engaging in volunteer activities.This study examines the relationship between volunteer work and six aspects of personal well-being: happiness, life satisfaction, self-esteem, sense of control over life, physical health, and depression, using data from the Americans' Changing Lives panel study (N = 2,681). The authors argue that previous research has often overlooked the antecedents of human agency, focusing instead on the consequences of volunteer work. They find that volunteer work enhances all six aspects of well-being, and that individuals with greater well-being invest more hours in volunteer service. The study also explores the reciprocal effects of personal well-being and volunteer work, suggesting a positive cycle of selection and social causation processes. The results highlight the importance of both individual characteristics and social integration in shaping the relationship between volunteer work and well-being. The authors conclude by discussing the implications of their findings for understanding the mechanisms through which volunteer work contributes to well-being and the role of self-selection versus social selection in engaging in volunteer activities.