While great progress has been made in documenting that organizational practices affect workplace inequality, little is known about how managers in particular may shape the careers of the employees below them. Using unique longitudinal personnel data on managers and their subordinates, this study identifies and tests for evidence of three distinct mechanisms by which managers potentially influence the assessment of employee performance in the workplace: (1) social network influence between employees’ current and former managers; (2) manager–manager (horizontal) homophily; and (3) manager–employee (vertical) homophily. I find evidence of the independent effects of all three mechanisms of managerial influence on the outcome of disagreement in the performance evaluation ratings of the same worker between former and current managers. In particular, my results stress that both managerial network influence and horizontal homophily affect the process of employee performance assessments, over and above the well-studied vertical homophily mechanism. I conclude by discussing the theoretical implications of these findings for future research regarding the interactional aspects of workplace inequality within contemporary organizations.