No Child Left Behind highly qualified teacher standing is awarded without regard to certification route or past performance. A bachelor's degree, state certification, and subject matter competence are sufficient for highly qualified teacher status according to the 2001 NCLB Legislation. The overarching goal of this study was to delineate qualifications, practices, characteristics, and experiences of teacher effectiveness beyond the NCLB highly qualified teacher definition. The study proposed a comprehensive conceptual model and definition of teacher effectiveness. This research advanced the discussion of teacher effectiveness in response to inconsistencies regarding what constitutes teacher quality and effectiveness. Is teacher quality and effectiveness determined by credentials or performance or both and to what degree? A mixed methods multiple case study with a threefold purpose was conducted. First, the study explored and described teacher practices in classrooms taught by NCLB highly qualified teachers. Second, the effectiveness of teachers' classroom practices was explored and described by observed planning, management, and delivery of instruction. Third, the study explored teacher and principal perceptions of effective teachers' characteristics and experiences. Teacher effectiveness was explored in four elementary schools with 20 teacher participants. Principals and teachers provided data on teacher qualifications, characteristics and classroom practices. Data collection methods included a teacher survey, principal and teacher interviews, teacher observations, and document reviews. Findings indicated teacher effectiveness was comprehensively defined by the holistic integration of teacher credentials, personal characteristics, and classroom performance. Personal attributes and the response to professional development of effective teachers were detailed. Narrative and descriptive statistics detailed observed classroom practices in terms of planning, management, and instruction.