A recent movement in teacher education research encompasses working with and through theory. In response to the call from Jackson and Mazzei (2013) to use theory to think with data and use data to think with theory, the author hopes to portray the complexities of teacher learning by avoiding models of teacher learning and development that tend to reinforce positivist, linear conceptualizations of expertise. In this article, the author puts to work multiple concepts to produce a more complex reading of the transformation of teacher expertise. In particular, she uses post-coding analysis, and provide a diffractive reading of the entanglements within a mangle of practice. The purpose for this article is threefold. Primarily, the author revisits previously analyzed data from a veteran Reading Recovery (RR) teacher, Grace, in an attempt to understand the intra-action, or intertwined entanglements that materialize in relationship with/in each other. The author focused on smaller, meaningful, compelling situations that arose from her previous coding. In the study of RR teacher expertise, the author found that methodologies commonly used in qualitative research did not provide her with a way to consider the complexity related to the process of teacher learning. She conducted a qualitative case study aimed at understanding the expertise of RR teachers. In her first analysis of the data, she implemented the Model of Domain Learning (MDL) as a descriptive and analytic framework. The MDL offered a multi-stage, multidimensional lens with which to view cognitive and affective aspects of the development of expertise in teaching reading. However, the author found the MDL limited her ability to understand the intertwined elements related to development of teacher expertise. Thus, she engaged in a diffractive reading of the data and put other theories to work. Barad describes diffractive reading as the act of (re)turning to the data and attempting to understand it from different perspectives. To read her data diffractively, she turned to complex, non-linear thinking. Kohn (1996) suggests that everything, from the furniture, to the teachers' voice, to the climate within a classroom or school, influences learning experiences. To account for all these elements, human and non-human, that may influence teacher learning, the author engaged with the work of new materialists. New materialisms provided a different way to understand the complex, entangled, intra acting elements related to Grace's expertise.