This exploratory study utilized a conceptual framework for self-directed computer-assisted professional development (PD) to evaluate the implementation and outcomes of a six-month PD pilot program. The program was designed to enhance the English proficiency of Taiwanese bilingual school teachers through a computer-assisted learning platform. Using a narrative-based methodology, we constructed and analyzed vignettes from seven participating teachers using a conceptual framework that integrates motivation, self-management, platform readiness (ease of use), and self-monitoring. While self-directed computer-assisted PD offers promising opportunities for teacher development, this study reveals significant challenges, particularly in sustaining engagement and ensuring the platform aligns with teachers' specific needs. Drawing on these insights, we offer several recommendations for schools to enhance the effectiveness of self-directed computer-assisted PD across diverse educational contexts based on the study's conceptual model. These recommendations convey an overarching message: Self-directed PD should not be viewed as an isolated endeavor for teachers. Specifically, we underscore the importance of appointing a PD program administrator to facilitate the program model and guide teachers throughout the self-directed learning process.