This paper describes a framework which captures the knowledge, skills, and dispositions of teacher leaders who demonstrate the ability to work effectively with students and peers in their own classrooms and beyond. Data come from 10 in-depth studies of recognized, urban, middle-school teachers. During the study, participants came together twice for 3-day conferences to facilitate reflection on their leadership qualities and how they acquired them. The process revealed some early themes about teacher leadership: the importance of subject matter knowledge, the commitment of teachers to working collaboratively, and the unique challenges of teaching other teachers versus students. Through interviews and portfolio reviews, other themes emerged: the role of reflection in teacher growth, the sense of empowerment they shared, and their enthusiasm for continually innovating in the classroom. Using teachers' feedback, a framework was developed that captured leadership qualities in four dimensions: expertise, collaboration, reflection, and empowerment. By following the teachers' career paths, the study found that as the teachers developed high levels of skill in each of the four domains, they emerged as leaders. The importance of professional development experiences in cultivating participants' expertise, collaborative and reflective skills, and sense of empowerment is noted. (Contains 24 references.) (SM)