This study explores the impact of secondary traumatic stress (STS) on first-year teachers (FYTs) and the potential of trauma-informed practices (TIP) as a mitigating strategy. STS, which results from exposure to students' trauma, is a significant but underexplored issue in education. By examining the first year of teaching, this mixed-methods study investigates whether TIP reduces STS symptoms and improves knowledge retention in FYTs. Quantitative findings suggest that TIP can enhance TIP content knowledge and confidence and reduce STS, offering valuable insights for teacher well-being and retention, particularly in high-needs schools. This study contributes to the emerging literature on STS in education and highlights the importance of targeted support for first-year teachers.