The COVID-19 pandemic greatly impacted global health. Frontline healthcare workers involved in the response to COVID-19 faced physical and psychological challenges that threatened their wellbeing and job satisfaction. The pandemic crisis, alongside pre-existing critical issues, exposed healthcare workers to constant emotional fatigue, creating an increased workload and vulnerability to stress. Maintaining such stress levels increased their levels of anxiety, irritability and loneliness. Evidence shows that the Psychological Capital (PsyCap) was a strong protective factor against these stressors. The aim of this study was to analyze the level of job satisfaction among health workers facing the COVID-19 pandemic. The possible antecedent factors to satisfaction and the role that PsyCap plays in preserving and fostering higher levels of job satisfaction were investigated. A total of 527 healthcare workers from different areas of Italy were recruited for the study. The results revealed that psychological stress factors have a considerable impact on job satisfaction. All four predictors (Stress Vulnerability, Anxiety Symptoms, Loneliness and Irritability) had the potential to decrease job satisfaction. Loneliness had a more significant effect than other factors assessed in this study. Moreover, the results showed how PsyCap could decrease the effects of psychological stressors on job satisfaction. Consistent with previous studies, our findings show that PsyCap could alleviate negative impacts in work-related circumstances.