Drawing from data collected by the National Center for Education Statistics (NCES) for the years 1987-88, 1990-91, 1993-94, and 1999-2000, we investigated secondary principals' educational attainment, teaching experience, and professional development. We found that throughout the years, secondary principals have been active in attaining advanced academic degrees (e.g. masters, doctorate), have increased their years of teaching experience before obtaining the principalship, have a stronger background in instructional leadership, and have been striving to enhance their professional skills and knowledge base. (Contains 8 tables and 2 figures.)