Seeking to identify conditions that support newly implemented evidence-based practices, this case study examined an implementation in which an existing agency was invited to move into the neighboring county to introduce its "housing first" practice with seriously mentally ill homeless adults. Using a constructivist methodology to elicit the narratives of key actors and observers about the implementation and its attendant controversy, this study found three issues at the core of actors' experiences: mode of presentation, use of an outside agency and the questioned uniqueness of the new practice. Barriers rather than facilitators dominated participants' interpretations of events despite significant researcher-observed facilitators.