Mission diminishment and creep which is the gradual dilution of a faith-based organisation’s founding spiritual or theological purpose poses a defining challenge for faith-based organisations of many traditions navigating secular environments, leadership transitions, and the competing demands of contemporary governance. This paper reviews scholarship from theology, organisational studies, personnel psychology, and the sociology of religion, to examine the mechanisms through which faith-based identity erodes and to identify the structural factors that protect against it. Central to the analysis is the phenomenon of values camouflage, a term this paper introduces, where leaders adopt the language of faith for employability or cultural fit without necessarily embodying the spiritual, ethical, or pastoral commitments necessary to sustain organisational mission. The experience of Mary Aitkenhead Ministries (MAM) a Catholic mission-based organisation operating across health, education, and welfare in the tradition of the Religious Sisters of Charity is used to illustrate how founding charism, when institutionally sustained through Catholic Social Teaching, careful stewardship, and community engagement, can function as ways to navigate secular pressures rather than a liability to be concealed. Finally, the paper identifies four interconnected domains of protective action: engagement with modernity, recruitment integrity, the preservation of founding charism, and ongoing organisational formation. It also offers six evidence-based recommendations for boards, leaders, and chaplains across faith traditions committed to maintaining theological distinctiveness without sacrificing organisational effectiveness. Limitations and future research opportunities are also discussed.