This study addresses the underrepresentation of fathers in autism research, particularly those with adult-aged autistic offspring. The authors explored the lifelong experiences and interpretations of fathers raising their autistic sons. Ten Hungarian fathers participated in a one-time semi-structured interview. Interpretative phenomenological analysis revealed four Group Experience Themes: ‘A revolving cycle around losing and regaining control’, ‘Crossing boundaries: accepting and adapting’, ‘Being in the world as a father: experiences of eternality and liminality’, and ‘Personal growth through pervading experience’. The findings highlight unique fatherhood experiences and offer implications for professionals and service providers. Lay abstract Being a father of an autistic son is a profound and complex experience. Fathers adapt to their autistic sons’ unique needs and are always in search of services to ease uncertainties about their sons’ present and future. We interviewed 10 Hungarian fathers who have adult-aged autistic children. We asked them about their experiences raising their autistic sons during childhood and adulthood. Our study focused on fathers of adult-aged sons because most research has studied mothers’ experiences of autistic children under 18 years old. It is also essential to know how to be like a father with adult-aged autistic children. Fathers shared their ongoing struggle with uncertainty, always seeking the best possible solutions for their sons. They also talked about how they understand and adapt to autism and accept their sons with their special, autism-related characteristics. The findings of this research provide a deeper understanding of fathers’ parenting experience, giving suggestions for professionals on supporting them and making their experiences valuable to the community of parents raising autistic children.