This study investigates the organizational structures, policies, and programmatic characteristics that distinguish high performing STEM high schools in Ohio, particularly those serving minority and economically disadvantaged students. Using a descriptive quantitative research design, data was collected from 16 STEM designated high schools to examine variations in governance type, enrollment policy, school origin, and access to informal STEM learning opportunities. The findings indicate that purpose-built STEM schools (programs that are originally established as STEM-focused schools and/or an early college program from inception) outperform converted schools as it relates to student academic outcomes. Independently governed schools with open enrollment policies also demonstrate greater inclusivity and stronger alignment with the state of Ohio’s STEM standards. However, significant disparities remain among minority-serving schools, particularly as it relates to informal STEM experiences such as extracurricular STEM opportunities. This study concludes with a proposed Four-Pillar Framework emphasizing governance autonomy, equitable access, robust partnerships, and sustained informal learning opportunities as essential for achieving equity-driven excellence in STEM education.