Few studies of work engagement have been undertaken within a civil service context. This study draws on data from an employee survey of the Irish civil service to explore the relationship between perceptions of ability-job fit and engagement and whether this relationship is mediated by meaningful work. It also examines whether the relationship between perceived ability-job fit and meaningful work is moderated by prosocial impact. The hypotheses for mediation are supported, but the findings for moderation suggest a tension between the ideals of doing public service work and those associated with making a difference to the lives of others.