Leadership is vital in engineering for individual career advancement and innovation across the profession. Although engineering educators have a key role in developing students' leadership, it is unclear what leadership training and experience they have. This research explores the sources of knowledge, experiences, and roles that engineering educators draw upon to inform their understanding of leadership. The second objective is to examine how, if at all, these experiences and roles influence educators' teaching of leadership. This study employed an exploratory qualitative approach and thematic analysis, drawing on interviews with 16 engineering educators in the United States. Findings indicated the importance of learning and practicing leadership in their current role, drawing on industry experience or speaking with professionals, leveraging personal experiences and relationships, and learning from formal training. These sources manifested in three ways in the classroom: intentional leadership instruction, informal leadership modelling and encouraging, and not feeling prepared to teach leadership. The findings contribute to a conceptualisation of the experiences that inform educators' understanding of leadership while pointing to the lack of formal training. Implications include considerations for faculty hiring and development, ways for faculty to draw on their experience, and suggestions for creating a culture supportive of leadership education.