ObjectiveProfessional identity formation (PIF) is the process of internalizing a profession’s core values and beliefs so that one begins to think, act, and feel like a member of that profession. PIF occurs over an individual’s professional socialization in stages, precipitated by critical moments or experiences. The purpose of this study was to answer the following: (1) What are the critical events for pharmacy student PIF in introductory pharmacy practice experiences?; and (2) How do these events support or challenge PIF? MethodsThis study used critical event narrative inquiry methodology. A critical event is an experience that creates a change in understanding and affects professional performance. Semistructured interviews were conducted with pharmacy students who completed introductory pharmacy practice experience rotations in community (first year) and hospital (second year) settings. Interviews were coded and analyzed using narrative analysis. ResultsTwelve first-year and 10 second-year students participated in this study. Narratives revealed that common experiential education experiences resulted in a deeper understanding of core role elements (ie, professional autonomy, responsibility, interprofessional collaboration, and patient-centered care), leading to changes in agency, knowledge, and anticipated future behaviors. While first-year participants’ narratives mainly focused on understanding pharmacist roles (“what”), second-year participants focused on understanding the process to fulfill those roles (“how to”). Emotions, assuming responsibility, external validation, and preceptor guidance supported these events. ConclusionCritical events in introductory pharmacy practice experiences affect and shape pharmacy students’ PIF. These events are relevant to pharmacy education because these experiences can result in changes in knowledge, agency, or future behaviors for students.