Paraprofessionals represent a substantial and growing portion of the workforce in professional organizations, yet most research focuses on the work and careers of elite professionals. Our qualitative study of 84 paralegals, lawyers, and management professionals in UK law firms redresses this balance. It reveals how professionals and paraprofessionals co-construct an illusion of mobility by engaging in two contradictory modes of boundary work — boundary stretching and boundary sustaining — situated within three domains: professional work, professional space, and systems of professional progression. Professionals send contradictory messages to paraprofessionals, by encouraging boundary stretching work, whilst simultaneously sustaining professional boundaries. Paraprofessionals’ illusion of career mobility contributes to becoming “stuck” in their careers, whilst preserving the elite status of the professionals. While developing a deeper understanding of paraprofessionals’ careers, our study makes two additional contributions. We develop theory on contemporary professional careers, arguing that the immobility of paraprofessionals serves a functional purpose in sustaining the elite status of professionals and we challenge emphasis on the liberating qualities of liminality in careers, emphasizing instead its dysfunctionality in perpetuating paraprofessionals’ illusion of immobility. Since paraprofessionals often come from disadvantaged backgrounds and lower-status universities, our study has broader implications for social mobility in the professions.