This dissertation is a constructivist grounded theory study of adolescent fathers who are involved in the juvenile justice system. The aim of the research was to identify factors that influence the development of an identity and role as a father among expectant and teen fathers involved with the justice system. Nineteen youth were recruited from a juvenile detention facility and a school district in a county with a high teen birth rate. Participants were incarcerated, supervised by juvenile probation, had a history of arrest or self-reported criminal behaviors. Observations were conducted to gather data about relations in the detention facility. Youth participated in individual interviews that took place in the detention center, school, or community. Observational and interview data were analyzed using constant comparative and dimensional analysis to construct a grounded theoretical perspective of the process of father identity development. Thirty analytic codes were considered to determine those most central to the process. Findings indicated that 1) adolescent fathers involved in the justice system can be assigned to one of four fluid categories --those who embrace fatherhood, those who are barred from fatherhood, those who are ambivalent about fatherhood, and those who reject fatherhood; 2) masculinity plays a prominent role in father identity development--many fathers hope for a boy and look forward to making a son into a man. Study findings suggest that nurses and other healthcare providers who work with youth in the juvenile justice system are in an opportune position to identify boys who are expecting or parenting a child. Expectant and teen fathers who embrace the father role can be supported to co-parent successfully in order to remain engaged. Those fathers who are barred, ambivalent or rejecting can be supported to reduce the barriers that interfere with father involvement among teens. The findings also indicate that teen father engagement, especially with daughters, might be improved if interventions were sensitized by gender. Youth who are young fathers and involved in the justice system would benefit from education about positive parenting practices, particularly those that challenge the highly masculinized and limited view of the father identity and role.