This thesis shows that foster youth can be active participants and agents in shaping their own lives, both in terms of developing and breaking relationships. The aim of the thesis is to examine the everyday lives of young people after entering various types of foster families, and to identify processes in various contexts that influence their sense of belonging. Three of the studies are based on in-depth interviews with 17 foster youth, and a fourth study also includes follow-up interviews with 15 of them. The study’s perspective views the family as socially constructed by means of interactive rituals in which both adults and young people are social actors. Study I demonstrates foster children’s motivation and aptitude for academic improvement, even despite previous severe problems in school. The study indicates that their satisfaction with school is related to both the quality of care they receive and their relations with peers. Study II illuminates the importance of both structure and warmth in foster youth’s everyday life. Routines normalize their daily life. Emotional warmth is created through doing things together. In particular, joking and laughing stand out as important inclusion practices. In study III the young people in kinship and network foster families are found to display the strongest social bonds to their foster families, and the young people in traditional foster families the weakest. Including network foster families in the study sheds light on the importance of adolescents’ active involvement in choosing their foster families. Study IV strengthens findings in the previous three studies about the importance of mutual activities and laughing together for the creation of social bonds in the foster family. Over time, adolescents in traditional foster families also have strengthened their social bonds to the foster family. Therapeutic support is found to be more common in the follow-up interview than one year before, and this unmasks the vulnerability of foster youth, and girls in particular. However, foster youth exhibit personal agency by still coping fairly well with their situation. Overall, this thesis shows that the sense of belonging in the family is strengthened if youth negotiate and take part in decisions concerning them and if the family is an ‘open foster family’ in its reception of the youth and their biological parents, but also that humour can serve as a door-opener into the foster family.