This article focuses on teacher commitment, and particularly on teachers displaying sustained high levels of commitment throughout their teaching careers (over 15 years). Graduates from one Teacher Education programme responded to an open-ended questionnaire conducted on 10 occasions concerning their work as teachers, from graduation in 1993 to 2013. Out of the 72 who responded on all nine occasions, eight teachers stating high levels of commitment throughout their careers were selected for additional interviews. A framework containing four commitment factors was used as the point of departure. Content analyses of the interview and selected questionnaire data then resulted in a revised framework of five factors: personal, teaching, school context, system context and professional development. Accounts from eight teachers with sustained high commitment illustrate the framework. The article offers an extended framework for understanding and categorising the factors that contribute to teacher commitment.