Drawing on the literature on sector imprinting, we examine whether private sector experience is related to organizational commitment among senior public managers. We also explore the role that position and organizational tenure play in shaping that commitment, since tenure length is often associated with greater commitment, and assumed to be an important mediator of employee and organizational outcomes. Multi-level analyses of a large multinational survey of senior managers from the central governments of 16 European countries indicate that a greater proportion of private relative to public sector work experience is associated with weaker organizational commitment among senior public managers. In addition, position and organizational tenure are both positively related to commitment. Mediation analysis suggests that the mechanism through which the negative effect of private sector experience on senior managers’ organizational commitment operates is individuals’ shorter tenure in the same organization. All of these results hold when we analyze the affective, continuance, and normative dimensions of commitment separately.