Responding to the debate about the advantages and disadvantage of family firm professionalization (Songini, 2006), we apply agency and stewardship theory to examine how the control system factors of professionalization (PRO) affect employee engagement (EE) in family and non-family firms. Further, we test the moderating effects of entrepreneurial orientation (EO) on that relationship (model 1) considering that firm EO factors encourage EE antecedents, such as challenging task, trust, excitement (Haar & White, 2013), and role clarity (Monsen & Boss, 2009). In addition, we also examine 3 other moderating models, i.e.: employee rank (RANK) on PRO–EE relationship (model 2), PRO on EO–EE (model 3), RANK on EO–EE (model 4); and 2 mediating models, i.e.: EO on PRO–EE (model 5) and PRO on EO–EE (model 6).