Sustaining large health promotion interventions in hospitals is notoriously difficult, and our understanding of sustainability enablers remains peripheral. This case study examined sustainability of Canada's largest hospital based health promotion facility: The Wellness Institute at Seven Oaks General Hospital in Winnipeg. Seven sustainability enablers were identified: (1) Community support and ownership; (2) Consistent, supportive, visionary leadership; (3) Well-managed operations; (4) Limited service overlap and duplication; (5) Alignment with the healthcare system; (6) Consistent, professional staffing; (7) Leading-edge facilities and services. Four sustainability barriers were identified: (1) Alignment with the healthcare system; (2) Limited funding; (3) Service duplication; (4) Sub-optimal location. Results can support leaders with future planning and implementation of health promotion programming.