Background: Children with profound intellectual and multiple disabilities need support to function in an optimal way. However, there is a limited knowledge about the role of external personal assistants working in the children's home. Materials and Methods: A mixed method study was performed including qualitative data from interviews with 11 Swedish parents and nine external personal assistants and quantitative data from questionnaires answered by 60 families. Results: For the child, the assistant's role was one of reinforcing, meaning supportive and empowering, and the child needed a high level of assistance. For the family, the role was one of balancing and the external personal assistant was more often found to assist in activities away from home while parents tended to assist within home and in family unit activities. Conclusion: In planning and implementation of external assistance, the child's needs as well as considerations of the whole family should be regarded.