Line manager involvement in HRM is an increasing trend across Europe. With the numbers of employees taking advantage of work-life balance policies also on the increase, line manager responsibility for this specific policy area is likely to become more marked. In this paper, we argue that line managers have a critical role to play in the career development of reduced-hours employees, but that due to a number of cultural and institutional processes, the extent of this involvement is likely to be limited. Using qualitative data from interviews with police managers and police officers who have reduced their hours, we argue that gendered assumptions, deeply embedded in taken-for-granted organisational practices and structures, operate in ways that encourage line managers and reduced-hours workers to locate career barriers in the psyche of the latter. The implications of these processes for line manager involvement in the career development of reduced-hours professionals are explored and explicated. A template is appended.