America's urban public schools and their students are in dire need of a durable and committed corps of teachers, teachers who are willing to stay in education long enough to make a difference in the conditions of those schools, and most importantly, in student achievement. Many traditional teacher education programs critique alternative programs such as Teach for America for the relatively short (two-year) commitment that is required of its recruits, but do teacher education programs fare better in preparing novice teachers to stay in urban education? Ultimately the authors ask: What is the role of the many experiences in the lives of beginning teachers that contribute to the development of their teacher identities--from what they bring, from their teacher education experiences, from their experiences in their school settings? In order to explore this question, for five years the authors have been following the development of teacher identities and career choices of a cohort of graduates of the Multicultural Urban Secondary English (MUSE) Credential and MA program at the University of California, Berkeley (UC Berkeley). One of the main goals of the MUSE program is to prepare teachers to teach some of the most underserved students, those who come from conditions of poverty and populate their low-performing, urban schools. The authors chose to capture their findings on teacher identity through case studies. The authors include three case studies from the cohort under study. For their three cases, the authors describe Natalie who fits the traditional definition of a stayer in a high needs school; Margo who has remained in a significant position in urban education, even though she has left classroom teaching; and Sally, a leaver who seems to be a casualty of dysfunctional urban schools. (Contains 3 notes.)