While the academic and social success of two-way immersion programs in the public school sector is widely documented, little research has been conducted on how US Catholic school leaders have managed this whole school reform. Through an exploratory case study, the motivations and perceptions of 28 Catholic school administrators and change agents/key informants (including teachers, assistant/vice principals, board members, and consultants) from ten Catholic elementary schools were interviewed regarding the conversion to a dual language immersion model. Findings considered how Hargreaves and Fullan's (2012) concept of professional capital and Grace's (2002; 2010) notion of spiritual capital contributed to the leaders' capacity to meet the school's change needs. Most schools began with limited resources and knowledge about the technical aspects of dual language immersion, but made use of key local and national social networks as well as drew upon their own biographies and Catholic vision to increase enrollment and engender professional learning among faculty. Implications for future research and practice include attention to the nuances of academic excellence and the complex language history of Catholic schools. The study concludes with recommendations for Catholic school principals. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]