Essential elements of a housing intervention designed to serve people who are homeless or risk becoming homeless, have severe mental illness, and may have a substance use disorder are described and summarized in a logic model. Characteristics of the target population, the community and the service system are examined, and how this program serves to address the issues. The effectiveness of this intervention appears to be the result of the organizational characteristics. The organizational structure and climate provide: (a) integrated services under one ‘‘umbrella’’; (b) flexible, responsive service delivery; and (c) a treat-ment philosophy which builds on the strengths of residents through effective staff-resident relationships.