Despite there being a significant amount of research investigating workplace learning, research exploring firefighter workplace learning is almost nonexistent. The purpose of this qualitative multi-case study was to explore how firefighters conceptualize, report, and practice workplace learning. The researcher also investigated how firefighters learn informally in the workplace and how that informal learning was manifested. A qualitative multi-case research study of six full-time career firefighters employed by a fire department in New York State was conducted. Data were collected through field observations, interviews, and document analysis. The data were analyzed using grounded theory analysis as detailed by Charmaz (2006). Several themes emerged from the data analysis revealing how firefighters learn in the workplace. Findings indicate that firefighters learn necessary workplace information through both formal and informal learning practices. Firefighters learn formally in the workplace by (a) attending the fire academy, (b) participating in the in-service training programs, (c) taking external fire service courses, (d) attending college-level fire science programs, and (e) teaching and instructing. Firefighters learn informally in the workplace (a) through practice, (b) from each other, (c), through self-directed learning activities, and (d) from prior exposure to the fire service. These findings highlighted a complex, hybrid interaction between formal and informal workplace learning activities. The findings present implications for both fire service practice and policy. Findings from this study suggest workplace learning may be enhanced through training fire officers to identify and foster firefighter's informal workplace learning practices. The policy implications for fire department managers and trainers include improving firefighter informal learning in the fire service through the provision of support, resources, and time for learning activities as well as by developing mechanisms to record and document the time spent on informal learning activities. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]