Purpose: The aim of this study is to contribute to a better understanding of the effects of digital sources on the works and professional development of mathematics teachers. In line with this aim, the microlearning experiences of an experienced secondary-school-mathematics teacher who is pursuing a Ph.D. in a university, in an e-learning environment is the focus of this study. Design/Methodology/Approach: The study design is a narrative analysis. The researcher's diaries and interview recordings were analyzed in this context. The researcher diaries were written by one of the researchers, a PhD student mathematics teacher who took an active role in the practice.In addition, the semi-structured interview recordings with the same teacher are included in the research as data and documents, and they were analyzed in detail. The diaries of the teacher, the researcher, which are kept during the microlearning period and the interviews were analyzed using the content analysis method. Categories and codes were created as a result of the analysis. Findings: As a result of the analysis, it was identified that the teacher especially focused on the teachers’ concerns before teaching using microlearning and how these concerns change in time, the process of preparing digital lessons, student observations during the implementation, and changes within herself in diaries and interviews. Highlights: The study has revealed important results in terms of supporting e-learning. It may be recommended to integrate micro learning and micro content into mathematics and other courses. By eliminating the limitations of the research, comprehensive research of qualitative, quantitative, or mixed type can be conducted with more participants.