With the push by government and business leaders for greater emphasis on STEM education at all grade levels, STEM leaders (i.e., educational leadership and teacher leaders) are challenged to pioneer integrative praxes that prepare students for success in a scientifically and technologically driven society. Additionally, these STEM leaders must transverse the barriers of developing transformative educational experiences that involve diverse stakeholders. This study utilized a modified Delphi technique to investigate what STEM leader skills, competencies, and qualities are identified as critical by STEM professionals within integrative STEM education. Findings are presented for the following seven themes: mission and culture, equity and social responsibility, infrastructure and programming, curriculum and instruction, professional growth, evaluation and assessment, and extended learning. These findings may inform the development of courses and programs that prepare or provide professional development for STEM leaders.