(1) Background: Professional driving is a stressful occupation that requires high levels of attention and decision-making, often leading to job stress. Impulsiveness, a personality trait characterized by a tendency to act without forethought, has been associated with negative outcomes such as anxiety, stress, and risky behaviors. Mindfulness has been proposed as a potential strategy for reducing job stress in various occupational settings. However, little is known about the relationship between these variables. This study aimed to investigate the mediating role of mindfulness in the relationship between impulsiveness and job stressfulness perception among professional drivers. (2) Methods: A total of 258 professional drivers from Poland, Lithuania, and Slovakia, have completed self-report questionnaires: Impulsiveness-Venturesomeness-Empathy; Subjective Assessment of Work; Five Facet Mindfulness. (3) Results: Results indicated a positive correlation between impulsiveness and job stressfulness perception, and a negative correlation with mindfulness. Mindfulness partially mediated the relationship between impulsiveness and job stressfulness perception. Additionally, variations were identified in the perceived work environment factors and mindfulness among drivers based on their country of origin. (4) Conclusions: The findings suggest that mindfulness could be a useful approach for reducing job stressfulness perception among professional drivers with high levels of impulsiveness. Given the implications of job stressfulness for professional drivers’ health and safety, developing mindfulness interventions tailored to their specific needs could be a promising direction for future research and intervention development.