Objective: This study aimed to clarify the association between informal support from occupational health staff outside the workplace and the competencies of occupational health nurses. Methods: A self-administered questionnaire was distributed to occupational health nurses in the workplace. Multiple regression analysis was performed; the total score of the competency scale for occupational health nurses was used as the objective variable, the scores of the off-the-job support scale (both total and subscale scores) as the explanatory variable, and basic characteristics and items related to the workplace as the adjustment variables. Results: The analysis was performed on 176 individuals. As a result of multiple regression analysis, the non-standardized regression coefficient (B) for the total off-the-job support for occupational health nurses’ competence was 0.72 (95% confidence interval: 0.32–1.13). For each function, the coefficient for emotional support was 2.11 (0.87–3.26), evaluative support was 1.84 (0.87–2.81), and informational support was 2.07 (0.73–3.41). Conclusions: The results suggest that both the overall and functional classifications of workplace support are related to occupational health nurses’ competencies.

Objectives: This study aims to examine the career development trajectories of occupational health nurses through career changes. Methods: Semi-structured interviews were conducted with 10 occupational health nurses who had more than 5 years of practical experience as occupational health nurses and had changed jobs at least once after starting their careers in this field. The career development process was analyzed using trajectory equifinality modeling (TEM). Results: The participants were in their 30s to 50s and had experienced up to 4 job changes. The participants shaped their careers by seeking work styles aligned with their values and visions while integrating diverse experiences into their practices. Their career development trajectories were categorized into three phases: Phase I—Foundation Building; Phase II—Exploration of Growth and Career Transition; and Phase III—Integration of Career Transition and Self-Realization. A cyclical transition between Phases II and III was observed, suggesting the potential for flexible career expansion in response to changing social needs. Conclusion: Occupational health nurses followed a career trajectory characterized by taking on new roles and experiences through career changes, broadening the scope of their professional expertise, and shaping their careers in an autonomous and self-directed manner.