Family leisure is conceptualized as engagement and satisfaction with experiences that involve joint participation in activities with other family members during one’s free time. Although family leisure has been linked to family functioning, the process by which family leisure contributes to family functioning, particularly in the context of leisure constraints, has yet to be explicated. Guided by theory, this study examined the relationships between leisure constraints and family functioning of United States Army personnel who have recently experienced deployments and evaluated the role of family leisure between these relationships. Two theoretically competing models were empirically tested to determine whether family leisure mediated or moderated the relationships between leisure constraints and family functioning. Leisure constraints were conceptualized as factors that inhibit a person’s ability to engage in leisure or derive satisfaction from leisure; these leisure constraints fall under one of three domains: structural constraints, interpersonal constraints, and intrapersonal constraints. For this study, relevant leisure constraints for United States Army personnel were identified. Structural constraints were defined as tangible, contextual factors that influence a person’s ability to function effectively in a leisure setting; perceptions of financial management were identified as a salient structural constraint for this population. Interpersonal constraints were defined as relationship factors that inhibit a person’s ability to function in a leisure setting; relationship warmth was identified as a salient interpersonal constraint for this population. Intrapersonal constraints were defined as perceptions of personal or internal processes that inhibit a person’s ability to function in a leisure setting; coping with the military lifestyle was identified as a salient intrapersonal constraint for this population. Family functioning was measured as a latent concept that included dimensions of family flexibility and family communication, both of which have been identified by the military as vital components to creating military family readiness. The construct of family leisure encompassed aspects of leisure engagement and leisure satisfaction. The first model was theoretically derived from leisure constraint theory and examined whether family leisure served as a mediating influence between leisure constraints and family functioning. The second model, theoretically derived from effort recovery theory, evaluated family leisure as a moderating influence between the variables of interest, leisure constraints and family functioning. The study sample consisted of 222 active duty United States Army personnel stationed in the continental United States, who were in a committed romantic relationship for at least two years, and had at least one adolescent child between the ages of 11 and 18. Studying military members who have significant others and adolescent children is important as the military operating environment is one characterized by high rates of transition and instability that can have a significant influence on informal networks, namely familial relationships. Family relationships are highly correlated with military family readiness, the ability of the family to effectively respond to military needs. Results indicated that family leisure fit best as a mediator and did not fit as well as a moderator for this sample of military members. More specifically, family leisure partially mediated the relationships between the leisure constraint variables of interest and family functioning. The leisure constraints of financial management and relationship warmth were significantly associated with family functioning. However, the direct relationship between military coping and family functioning was non-significant. For the indirect relationships, all leisure constraints were significantly associated with family leisure, and, in turn, family leisure was significantly associated with family functioning. This model fit similarly when accounting for the depressive symptomology of the active duty service member. In the competing model, no moderating effects were found for the study variables of interest. Results from this study can be used by service providers and policy makers who can advocate for family leisure as a leverage point for promoting healthy military families post-deployment. Practical applications include disseminating information to military families about leisure resources to provide families with new avenues to promote positive family functioning.