This study investigates the paradigm of spiritual leadership developed through renunciation (Tyag) and meditative austerity (Tapasya) in the life of Prajapita Brahma Baba (born Lekhraj Kripalani, 1876–1969), the founder-figure of the Brahma Kumaris spiritual movement. Moving beyond conventional definitions of renunciation as mere physical withdrawal or ascetic deprivation, this paper analyzes how Brahma Baba redefined Tyag as the internal detachment from ego, body-consciousness, and material attachments, and Tapasya as the continuous stabilization of intellect in divine remembrance (Parmatma Smriti). Through a historical-biographical framework spanning six distinct phases between 1936 and 1969, the paper traces his transition from a prosperous diamond merchant in Sindh to a visionary spiritual leader. The analysis demonstrates how internal purity (Pavitrata), endurance (Sahanshilta), and selfless service (Sewa) enabled the movement to navigate major socio-historical crises, including social opposition to celibacy and the turmoil of the 1947 Partition of India. Ultimately, the study highlights how his final years exemplified the "Angelic Stage" (Farishta Jivan), offering a sustainable model of institutional leadership grounded in personal example, humility, and spiritual resilience.