Background: Historically, research exploring the impact of having a child with an Intellectual Disability (ID), has focussed exclusively on mothers. The present study aimed to investigate fathers' experiences of parenting a child with Down's syndrome (DS), their contributions, influences on family functioning and inclusion in their child's support provision. Method: Semi-structured interviews were conducted with 15 fathers. Interviews were analysed using Grounded Theory (GT). Results: Fathers' adjustment appeared to be on a fluid trajectory with three key categories influencing this: "Accommodating the Child," "Adapting the Parental/Spousal Role" and "Adapting Society." Conclusions: The accounts uncovered fathers' adjustment trajectory to parenting a child with DS, concluding that despite practical and emotional challenges, fathers employed strategies to achieve positive adjustment. Fathers identified the need for services to recognize their role and involve them in their child's support provision. Implications for clinical practice and future research are discussed.