Purpose: This qualitative study extends jigsaw lesson study (JLS) by focusing specifically on the impact of feedback on teacher candidates' (TCs') professional knowledge and instructional growth in the teacher-educator classroom. Design/methodology/approach: For this study, JLS took place in two different methods courses and followed the lesson study (LS) framework using the small group rotations of JLS. In each course, the JLS small group teams taught another team before receiving feedback and revising their lessons. Then they would teach another group. After each iteration, teams debriefed and reviewed the feedback to revise their lessons and prepare for reteaching. Following the JLS process, TCs reflected on the impact of feedback in a post-survey that was analyzed, coded and aligned with their lesson iterations and revisions. Findings: Both integrated language arts (ILA) and math TCs reported that receiving peer feedback improved their lessons, instructional materials, revisions and student engagement. Through collaboration, TCs valued peer dialog, multiple perspectives and TCs learned to provide and receive constructive feedback professionally. Overall, feedback and collaboration helped strengthen their lesson planning as they considered multiple perspectives. Feedback helped TCs consider differentiation and the diversity of learners as well as student engagement while building their professional knowledge. Originality/value: Although a previous study has shown an impact of JLS in ILA teacher-education courses with a broader scope in mathematics courses, this study focused on the JLS process in two teacher-education courses. Furthermore, current research tends to focus on the LS process, but this study focused specifically on TCs' perceptions of the impact of feedback of their professional and instructional growth.