The majority of newly qualified teachers in New South Wales, Australia, begin their careers as casual teachers in fragmented employment contexts which make it difficult to build on the knowledge base gained at university through continuous, and continuously evaluated, practice in a classroom. This study explored the experiences of early career casual teachers and investigated the effect of fragmented employment contexts on the process of developing professional knowledge and practical competence in the first two years of teaching. The study employed a mixed methods research design utilising a collective case study together with a postal survey-questionnaire to gather both qualitative and quantitative data. Results indicated that the process of learning to teach in contexts typified by multiple schools, multiple classrooms, multiple communities and with multiple students exacerbated the problems encountered by all beginning teachers and provided few mechanisms by which casual teachers were able to resolve them to their own professional satisfaction.