Despite the high rate of co-occurring medical conditions experienced by individuals receiving assertive community treatment (ACT), this comprehensive service model continues to be considered primarily a mental health intervention. Without compromising fidelity to the model, ACT can serve as an ideal platform from which to provide both primary and behavioral health care to those with complex service needs. Using a case example, this article considers the transformation of the ACT mental health care model into an integrated health care delivery system through establishing nursing and primary care partnerships. Specifically, by expanding and explicitly redefining the role of the ACT nurse, well-developed care models, such as Guided Care, can provide additional guidelines and training to ACT nurses who are uniquely trained and oriented to serve as the leader and coordinator of health integration efforts.