Some employees perceive that supervisors do not accurately reflect employees' performance or effectively differentiate among employees' performances during performance appraisals (PAs). Other employees believe the performance feedback they receive is not valuable for supporting their career development (CD). Employing leader-member exchange (LMX) theory and the distributive and interactional justice dimensions of organizational justice theory as the theoretical framework, this correlational study examined the relationships among LMX and employee-supervisor relationships (ESRs) and the relationships' influence on employees' CD through the mediating effect of employees' perceived efficacy of the PA process. Participants consisted of 44 defense contractor employees in the United States who completed a combination of 4 validated survey instruments (LMX-7, Interactional Justice, Appraisal System Satisfaction, Perceived Career Opportunity) and 1 demographic instrument. Results from the structural equation model, using partial least squares analysis, indicated significant (p < .001) positive relationships between the independent variables of LMX and ESR, the dependent mediating variable PA, and the dependent variable CD. The results indicated that a positive relationship between LMX and ESR will influence employees' CD through the mediating effect of employees' PAs. The implications for positive social change include the potential to improve communications between employees and supervisors, increase organizational performance by increasing employees' job satisfaction, potential benefiting career development for improving employees' families' quality of life, and contributions to the communities.