This study investigated relationships between personality types and job satisfaction, and performance among school food service dietitians. An online survey was conducted on 200 school dietitians from March 1 to 31, 2022. Of the personality type factors, extraversion, openness, agreeableness, and conscientiousness were positively correlated with job satisfaction, whereas neuroticism was negatively correlated. Extraversion, openness, agreeableness, and conscientiousness were positively correlated with job performance, whereas neuroticism was negatively correlated. Regression analysis conducted to determine the effects of personality types on job satisfaction revealed conscientiousness predicted satisfaction with items of the job, agreeableness predicted satisfaction with supervisor’s supervision, and extraversion predicted satisfaction with colleagues. On the other hand, neuroticism was a negative predictor of satisfaction with the job, supervisor’s supervision, colleagues, and work environment items. Analysis of the effects of personality types on job performance established that openness was a positive predictor of satisfaction with roles of the organization and team, and of conscientiousness for the job, innovator, and organizational roles. In contrast, neuroticism negatively predicted satisfaction with job role items. Further studies are required to explore these relationships more closely by incorporating other major factors related to personality characteristics, job satisfaction, and job performance of dietitians working in various fields.