As proactivity becomes vital for organizational success, retaining proactive employees becomes increasingly important, making the relationship between a proactive personality and turnover intention a key research topic. While existing studies have largely depicted turnover as a consequence of dissatisfaction and have identified negative indirect relationships, this study seeks to challenge that perspective by proposing that, in today’s boundaryless career environment, people also engage in voluntary turnover for career advancement. Using a self-regulation career management model, we propose that proactive employees set ambitious career goals influenced by career aspirations, leading them to seek external opportunities and thus exhibit higher turnover intention. However, when organizations implement career management practices, this relationship weakens as proactive employees perceive opportunities to achieve their goals within their current organizations. We tested these hypotheses with a sample of 342 respondents using the SPSS macro PROCESS. The findings support our propositions, revealing a positive indirect effect through career aspirations, which diminishes when perceived organizational career management is strong.