Building on the epistemological foundations of constructivism (Creswell, 2014) and qualitative research methodologies, a FADE framework (Reinking and Bradley, 2008) and a case study approach (Merriam, 2002) were selected to develop an understanding of preservice teachers' thinking about student learning during their planning, teaching, and reflection through the lesson study (Lewis, 2009) process. Through qualitative methodology, the triangulation of data occurred using qualitative data sources: (a) pre and post interviews, (b) participatory field notes, (c) research lesson plans, (d) debriefing interviews, (e) field notes created by the preservice teachers. Each data source was analyzed individually and then compared across the case providing a deeper understanding of how preservice teachers think about student learning in the context of lesson study including how: (a) preservice teacher grew their thinking about student learning, (b) preservice teachers were better able to observe and look for evidence of thinking about students' learning, (c) the lesson study process allowed them to work as a team, (d) they associated lesson study with being a positive learning experience. This research provides additional insight into how teacher preparation programs can strengthen preservice teachers learning in classrooms through lesson study (Darling-Hammond, 2009; Lewis, 2009; Lewis et al., 2012). It also provides opportunities for further research on connecting planning, reflection, and teaching practices as well as, how to build connections between mentor teachers, preservice teachers, and teacher preparation programs (Parks, 2009).