The demands of the twenty-first century require effective and sustainable use of Information and Communication Technologies (ICTs) in education. Various ICT strategies and initiatives across South Africa have not resulted in system-wide, sustainable ICT integration in schools. Although the roles of principals are acknowledged in educational management, the question remains how principals influence teachers' effective and sustainable integration of ICT through teacher professional development (TPD). A matrix of theoretical criteria selected seven participants across diverse contexts. In-depth interviews produced an integrated dataset that revealed principals' patterns of influence, their perceptions and experiences, their leadership and management styles, their attitudes towards ICT integration, their knowledge on related ICT and related TPD issues, as well as their strategic thinking on ICT integration. The proposed theoretical framework illustrates the interrelatedness of aspects that influence principals' leadership through open distance learning.