The purpose of this study was to assess the impact of a mentored guideline implementation (Registered Nurses’ Association of Ontario Prevention of Falls and Falls Injuries in the Older Adult Best Practice Guideline) focused on enhancing sustainability in reducing fall rates and number of serious falls and the experience of staff in three acute care hospitals. The National Health Service (NHS) Sustainability Model was used to guide the study. Interviews and focus groups were held with 82 point-of-care professional staff, support staff, volunteers, project leaders, clinical leaders, and senior leaders. Study results supported the importance of the factors in the NHS model for sustainability of the guideline in these practice settings. There were no statistically significant decreases in the overall fall rate and number of serious falls. The results supported strategies of participating hospitals to become senior friendly organizations and provided opportunities to enhance staff collaboration with patients and families.