Understanding the factors that influence the behavior of front-line emergency medical services (EMS) providers is critical as these individuals can have a substantiveimpact on the health of the patients they treat. EMS providers can be examined as “street levelbureaucrats,” focusing specifically on the interrelationships between rules, discretion, and influence that surround the primary tasks of the occupation. To begin a conversation on this critical public service a mixed methods research design is employed, using qualitative data to inform quantitative data collection and analysis. The initial phaseconsisted of content analysis of policy documents, 30 semi-structured interviews, and three focus groups. A web-based survey was then employed to measure variables of interest emerging from the qualitative data collected. Results indicate that substantial rule complexity is the norm. General ruleabidanceis notable, especially in cases of extremely minor or very severe medical or traumatic emergencies. Where discretion is unrestricted sources of influence such aspatient characteristics, peers and supervisory staff, medical command physicians, and situational factors were notable. In other cases rules were not sufficient to regulate behavior, and rule application was complicated by factors such as paramedic communication skills, patient identity, and bystanders. Deviation from rules occurred in several instances as a result of influences from patient need, occupational culture, and peer paramedics. Results from quantitative analysis show support for several relationships of interest. Experienced paramedics are increasingly likely to bend rules in the face of patient benefit, and paramedics who are better able to understand the perspectives of others are likely to exhibit a more favorable rating of patient worthiness. Theoretical contributions of this research include refinement of theories of street levelbureaucracy with attention to the nature of discretion in the unique context of EMS. Additionally, this study serves to bridge a gap between disparate areas of empirical research in the field of EMS, bringing together clinical, educational, and systems-level emphases. Practical contributions of this research improvement of patient care and outcomes by aligning discretionary behavior with clinical goals and patient outcomes,and the generation of additional considerations for improving initial professional education and on-going training of front-line EMS providers.