The purpose of this qualitative study is to expound upon the research conducted by R.L Brown (2004), W. Dygert (2000), J.T. James (2009), M. Daniels (2013) and B. Regan (2015). Their focus was to look carefully at the President-Principal Model (PPM) in order to better understand the efficacy of introducing this administrative team structure to private, independent, all-girls Catholic high schools. This study expands their work seeking what leadership skills, personal characteristics and values are necessary in presidents and principals who serve in all-girls Catholic high schools in the US and have adopted the PPM. The goal of any Catholic school that would like to administer through the PPM is to have a consistent description of these roles in order for the president and principal to work together toward student success. Through focus groups and checklists, patterns became evident as to which skills, characteristics and values were deemed most important in the building of a successful, collaborative, administrative leadership team. These details were the foundation for the creation of a guide to assist search committees and interviewing teams when selecting the best suited candidates for the positions of president and principal in all-girls Catholic high schools in the US. This research has determined that the success of this model was largely dependent upon the amalgamation of the leadership skills, personal characteristics and values relationship between the president and the principal. In addition, this study researched the when, why and purpose of the position of president in the current governance of all-girls Catholic high schools; how the President-Principal Model was formed; and what effect this administrative leadership model has had on the school community. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]