Learning science, technology, engineering, and mathematics (STEM) subjects starting at a young age helps prepare students for a variety of careers both inside and outside of the sciences. Yet, addressing integrated STEM in an elementary school setting can be challenging. Teacher leadership is one way to address this challenge. The purpose of this qualitative, descriptive case study is to understand how participation in the NebraskaSTEM Noyce Master Teaching Fellowship project impacted elementary STEM teacher leadership identities. Our findings suggest participation in the project contributed to different layers of teacher leadership identity (as a STEM learner, as a STEM teacher, and as a STEM teacher leader). These findings suggest professional development should be tailored to address empowering specific layers of STEM teacher leaders' professional identity. Other teacher leadership development projects may want to consider how to structure their projects to empower teachers based on the identities and experiences of those teachers.