The purpose of this research study was to consider the understanding and experience of a selected number of lay principals of diocesan secondary Catholic schools in Victoria as to the religious and spiritual dimensions of their leadership role and to identify what supported them in the discharge of their responsibilities in these domains of their leadership. Based on this purpose, I identified three research questions: 1. What is the understanding of lay Catholic secondary principals in Victoria, of their role as a ministry within the Catholic Church? 2. In what ways have principals experienced the spiritual and religious dimensions of their leadership role? 3. In what ways have principals sought and/or experienced formation beyond academic study which has enriched their practice of principalship? The theoretical perspective of the research is Interpretative Constructionism and the methodology adopted is Multiple Informant Case Study. The researcher has taken the stance of ‘interrogatory fellow traveller’ in relation to the research informants. The methods used to gather data are (a) focus group, (b) biographical written statements, (c) document analysis and (d) personal reflection in response to the previous three methods. In general, the findings of this research study suggest that lay principals of Catholic secondary schools who were informants in the study understand the role of principal of a diocesan secondary school as a ministry within the Catholic Church. While the informants did not use overtly theological terms to articulate this understanding, the accounts of their experience in principalship and the insights gained through reflection on their leadership behaviour have led them to believe that they are in fact exercising a legitimate ministry within the field of Catholic secondary education in Victoria. This research has brought to light a body of knowledge about the work of a group of principals which has not previously been subject to critical scrutiny. While the study is of intrinsic merit in recognising and describing the work of secondary lay principals, from an instrumental perspective these findings raise a number of issues relating to the preparation, induction and support available to newly appointed and continuing principals in diocesan Catholic secondary schools in Victoria. As a consequence the following propositions are offered: Further study using a wider informant group of principals is warranted to confirm the findings of this enquiry and to expand on the knowledge already gained. Such study might include parallel studies of lay principals in congregation-owned schools, in other states of Australia or in other countries where the Catholic Church has established schools as an agency of its evangelising mission in education. This study is of potential assistance to aspiring principals, principals and system authorities in the planning and development of appropriate professional learning and support, including formal academic study and formational opportunities. The findings confirm the importance for leaders and aspiring leaders in Catholic education of sound theological and spiritual education as a necessary part of their preparation for leadership, both pre-service and in-service. The findings confirm the significance of appropriate liturgical induction or commissioning for principals. It is suggested that one practical form of support for principals is the provision of access to regular professional supervision and spiritual direction. It is recommended that the process of appointment and induction of principals be undertaken more systematically, perhaps using the principles of project management, especially in relation to the identification of enhancing and inhibiting factors present within the staff community at the time of the appointment of a new principal. The findings indicate that schools have had varied experiences of developing a distinctive ethos and charism, based on a particular founder or group of founders. It is recommended that all diocesan secondary schools be encouraged to develop an appropriate charism and spirituality, based on the character of the local faith community and the history of the particular school. The findings point to the need for further development of an authentic spirituality of educational and faith leadership, based in the reality of principals’ lives as family and community members and educators in faith of their staff and wider community. Informants to the study indicated their awareness of the tension between occupying a leadership role in the Church and personal positions in conscience on matters of Church teaching. Some further study of this issue may be warranted.