This qualitative study identified influences on participation in physical activity among seniors living in the community and in long-term care facilities. A total of 24 seniors participated in individual face-to-face interviews. Through thematic analysis, the overarching theme identified that past experiences, life transitions, and future concerns influence seniors' participation in physical activity. This overarching theme helps explain the complexity of physical activity participation in later life. The subthemes included intergenerational influences, establishment of early physical activity patterns, family transitions over the life course, changing health status over the life course, and future health concerns. A greater understanding of an individual's life history is paramount for nurses to help increase participation in physical activity among seniors.