Although the double-edged nature of perfectionism is widely acknowledged, little is known about how it shapes employee career development. By combining two field studies, we provide a multiperspective insight into the relevance of both employee and supervisor perfectionism for employee career development. While we expected self-oriented perfectionism (SOP) to have an ambivalent role for career development, we proposed that socially prescribed perfectionism (SPP) in particular, but also other-oriented perfectionism (OOP), would show maladaptive relationships with career-related indicators. In Study 1 (N = 116), we focused on the employee perspective and how multidimensional perfectionism relates to career aspirations (operationalized via work motivation) and subjective career success. Employees high in SOP reported higher, whereas those high in SPP reported lower perceived career success. OOP was negatively related to intrinsic motivation, but positively explained extrinsic (social) motivation and amotivation. In Study 2 (N = 146), we examined the role of supervisor perfectionism in supporting or hindering employees' career development by providing or draining resources. Our results show that supervisors high in SOP - and partly in OOP are reluctant to delegate highly responsible tasks; SPP even increased the likelihood of assigning illegitimate tasks to subordinates. Our findings suggest that both employee and supervisor perfectionism may boost or thwart employee career development and success. We discuss that supervisor perfectionism may limit employees' opportunities for experiential learning.