Mothers of children with severe functional disabilities often assume roles that exceed the normative activities of parenting in relation to the intensity, complexity, and temporal nature of the family caregiver experience. This phenomenologic inquiry explored the lived experience of caregiving among mothers caring for an adolescent or young adult with severe cerebral palsy. Data were collected through semi-structured interviews with 11 mothers and analyzed using van Manen's approach. Analyses revealed four interrelated essential themes related to managing an unexpected life, balancing caregiver demands, assuming advocacy roles, and facing an uncertain future. Findings suggest the need for improved supports and services to optimize family caregiving during this transitional period of family life.