The Collaborative Initiative to Help End Chronic Homelessness (CICH) was established to provide housing and supportive services for individuals experiencing chronic homelessness. As part of this initiative, 11 projects across the country received funding to apply models of best practices to support their clients in housing. This paper reports on the experiences of the CICH projects in their use of Assertive Community Treatment (ACT) and Motivational Interviewing (MI), clinical practice models commonly used by CICH projects. A qualitative analysis identified five areas of challenge for the projects: (1) Incomplete and underdeveloped staff teams; (2) Incomplete understanding of the practice models; (3) Using the elements of the practice models; (4) Interagency teaming; and (5) Competing expectations of multiple federal agencies. The paper describes the specific challenges in each of the five areas as well as training approaches and gaps in training and the perceived benefits of the practice models as reported by project staff.