Despite incontrovertible evidence documenting effects of fathering on child outcomes, social work practice has unyieldingly resisted the pursuit of father engagement as a requisite outcome of competent clinical child intervention. Reasons behind this resistance are already well understood, and several promising programs have provided reassuring evidence that inclusion of fathers in clinical work with young children in higher-risk families is not only possible, but transformative. Yet despite the fact that the soil has been tilled and essential professional competencies needed for effective work with fathers identified, it is unlikely that comprehensive changes will ever take root without the social work profession embracing a coparenting and triangular perspective in all efforts on behalf of children and their families. In this article, main conceptual distinctions between triangular and “2 + 1” models are drawn, with accounts provided differentiating perfunctory from persistent assumption of a triangular model, calling on an inventive coparenting intervention for unmarried expectant parents as a case in point. This article also focuses on parallel changes in the institutional and community contexts in which social work practice is embedded that will be needed to better support the coparenting family once interventions have met with success in solidifying family triangles in children’s best interests.