Novice teachers often have difficulty transferring what they learn in teacher education programs to classroom practice. This is especially true for elementary school teachers who are expected to teach mathematics with reform-oriented methods. The purpose of this longitudinal case study was to examine the experience of one novice elementary school teacher over a 3-year period, and understand the factors that supported her to enact a reform-oriented practice in mathematics as she transitioned from being a preservice to inservice teacher. Influential mathematics education models, her commitment to learning, and school-based contexts affected her teaching identity and practices. To conclude, an argument is made for teacher education experiences to explicitly address mathematics teacher identity to support the enactment of reform-oriented practices.