Background: Recent empirical work shows that student teaching in a high-quality learning environment and with a highly effective cooperating teacher predicts the performance and retention of early-career teachers. Little is known about principal internships and their impacts on school leader outcomes. Purpose: To examine the characteristics of principal interns, internship schools, and mentor principals. Setting: Principal preparation programs and K-12 public schools in North Carolina. Sample: A total of 1,135 principal interns from 12 preparation programs in North Carolina over a 4-year period (2015–2016 to 2018–2019). Data: Preparation program data on principal interns and when/where their internship occurred and administrative data from the state of North Carolina, from 2011–2012 to 2018–2019, on all school personnel and schools. Research Methods: Descriptive statistics and multiple regression analyses to compare interns to noninterns, internship schools to noninternship schools, and mentor principals to nonmentor principals. Findings: We find that interns are more likely to be a person of color and have higher evaluation ratings and value-added estimates than teachers in their buildings. Internship schools have lower levels of quality than noninternship schools, particularly for interns of color. Mentor principals are slightly more effective than nonmentors. Conclusions: Our findings suggest that preparation programs and school districts could be working in closer partnership to make placements in high-quality learning environments and with more effective mentor principals. There is a need for future work to assess the geography of placements, the placement process, and the associations between placement schools and mentor principal characteristics and subsequent outcomes for principal interns.