Higher education physics has long been a field with a disproportionately skewed representation in terms of gender, class, and ethnicity. Responding to this challenge, this study explores the trajectories of "unexpected" (i.e., demographically under-represented) students into higher education physics. Based on timeline-guided life-history interviews with 21 students enrolled in university physics programs across Sweden, the students' accounts of their trajectories into physics are analyzed as "choice narratives." The analysis explores what ingredients are used to tell a legitimate story of physics participation, in relation to dominant discourses in physics culture, and wider social and political discourses. Results indicate that students narrate their choice as based on motivations of physics being a prestigious and challenging subject, of a deep interest in and a natural ability for physics, as well as a wish to use physics for contributing to the world. While most of these affiliations to physics has been documented in earlier research, the study shows how they are negotiated in relation to social locations such as gender, class and migration history, and used to perform an authentic and legitimate choice narrative in the interview situation. Furthermore, the study reports and discusses the possibility of conceiving the role of physics in students' lives as something beyond a "pure", intellectually challenging, and "prestigious" subject. In contrast, and with implications for widening participation, the stories of "unexpected" physics students indicate that physics can be reconceived as socially and altruistically oriented.