Access to job and study resources is important to enhance workers’ and students’ career optimism, respectively. Yet, it is unknown how these resources foster career optimism in young adults who work and study. Drawing on conservation of resources and self-determination theories, we examined the relationships between job and study resources and subsequent career optimism directly and indirectly via psychological needs satisfaction. Data were collected at two time points (4-week lag) from 256 working students (84% women; Mage = 20.08 years) recruited from one large, multi-campus Australian university. Using structural equation modeling, we found that study resources had a direct, positive relationship with career optimism, but job resources did not. We also found that both role resources had direct, positive relationships with autonomy, competence, and relatedness satisfaction. Only the satisfaction of autonomy needs was related to career optimism. Further, both job and study resources were indirectly related to career optimism via autonomy satisfaction. Overall, the structural model explained 21% of the variance in career optimism. These findings provide guidance on how university staff (e.g., career counselors and teachers) and those in the workplace (e.g., supervisors and managers) can enhance career optimism in this population of young workers.