St. Joseph's Health Care London (hereafter referred to as St. Joseph's) is a publicly funded hospital that has led mental health (MH) service system transformation in south west Ontario following directives from the Health Services Restructuring Commission (HSRC) (Sinclair 2000). This paper documents how provincial policy; HSRC directives; use of change management activities; organizational planning; and partnerships with other hospitals, community agencies and LHINs drove, shaped and accomplished the transformational change. The transformation included divestment of beds and related ambulatory services to four other hospitals, closure of beds and employment services and the construction of two state-of-the-art facilities. This paper documents the tracking of system performance measures and the outcomes that resulted.