This Harvard Business School case study, "Rob Parson at Morgan Stanley (A)," focuses on the complex performance evaluation of Rob Parson, a highly effective but interpersonally challenging employee at Morgan Stanley in 1998. It details the firm's cultural shift towards a "One-Firm Firm" vision under President John Mack, emphasizing teamwork and integrity, a stark contrast to Parson's individualistic and often abrasive style. Paul Nasr, Parson's manager, grapples with the dilemma of whether to promote Parson to managing director despite overwhelmingly negative internal feedback on his "team player" skills and interpersonal conduct. The case highlights the tension between individual revenue generation and adherence to a company's evolving corporate culture, presenting Nasr's options as he navigates Parson's potential promotion and future with the firm, using a comprehensive 360-degree performance review to illustrate the situation.