Professional teaching videos could be a powerful resource for shaping music teacher identity (MTI). This study examined preservice and inservice string instrument teachers' (SITs) (N = 3) preservice and inservice teaching videos to perceive similarities and differences in MTI to reveal professional growth over time. Results indicated that the SITs evolved with experience, knowledge of self, and self-assessment through reflection. MTI development results from teachers' receptiveness to professional development over time and their ability to adapt to changing contextual environments.