Background/Objectives: Paramedics are routinely exposed to high psychosocial strain due to the demanding and unpredictable nature of emergency medical work. This study aimed to examine psychosocial and behavioral factors—working hours, stress, burnout, and physical activity—associated with self-reported work ability among paramedics in Poland. Methods: A cross-sectional online survey was conducted between July 2023 and January 2024 among paramedics—whether active in Emergency Medical Services or holding a second degree and employed as a nurse—using the Polish version of the Work Ability Index and a stress and burnout assessment tool recommended by the European Commission. Statistical analyses, including Spearman correlation and group comparisons, were performed with a significance level of α = 0.05. Results: Work ability correlated positively with physical activity and negatively with age, stress, and burnout (p < 0.05). The strongest association was observed between stress and burnout (ρ = 0.837). Paramedics working in ambulance services reported significantly higher stress and burnout levels than hospital personnel (p = 0.001 and p = 0.002), although work ability did not differ by workplace. Conclusions: These findings indicate that psychosocial stress, burnout, and low physical activity substantially reduce work ability among paramedics, emphasizing the need for targeted preventive strategies—such as stress management, promotion of physical activity, and regulation of working hours—to support the health and sustainability of the emergency medical workforce.