The purpose of this qualitative single-subject case study was to identify the elements critical to crisis management professional development for school principals; the factors influencing the implementation of the National Incident Management System Phases of Emergency Management (2010) for principals; and the necessary elements for fostering effective collaboration in crisis management for principals. The conceptual framework for the study emanated from NIMS Phases (2010). The unit of analysis was principals employed by school districts in eastern Pennsylvania. Research findings indicate that principal preservice training did not provide adequate professional development. Formal professional development must focus on NIMS coursework and the implementation of the Incident Command System. Professional development must involve the building level administration, district level administration, and emergency first responders. Respondents implemented NIMS Phases (2010) by involving collaborative precrisis planning, drilling, and exercising with its crisis team and emergency first responders to conduct needs assessments, implement ICS, promote communication, conduct debriefings, and improve reaction time. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]