We examined self-engagement in job performance in a moderated mediation model where engagement moderated the relationship between organizational constraints and ratings of leadership effectiveness, and ratings of leadership effectiveness mediated the relationship between organizational constraints and organizational citizenship behaviors (OCBs). University employees representing diverse occupations completed measures of self-engagement, organizational constraints, and leader effectiveness. Supervisors provided ratings of OCB. Tests of mediated moderation using random coefficient modeling revealed that leadership mediated the relationship between constraints and OCB for highly engaged employees. Results are discussed in terms of highly engaged workers being attuned to stressors in the work environment that may compromise performance, potentially blaming leaders for the presence of these obstacles, thus causing withdrawal of effort on nonessential performance tasks.