The expanded therapeutic alliance, consisting of multiple interpersonal alliance relationships, is a common factor inherent to the practice of all systemic therapies. The following study has three specific aims: (a) Bring an expanded, multisystemic emphasis to the study of the therapeutic alliance in individual therapy; (b) Understand better the session‐by‐session relationship between alliance and psychological functioning, including distinguishing within‐person from between‐person variability by using multilevel modeling techniques; and (c) Explore the role of early attachment relationships and family‐of‐origin experiences in moderating the alliance‐psychological functioning relationship. Instead of taking only one or two alliance measurements throughout treatment like in the majority of previous research, we measured both alliance and psychological functioning continuously at each session for 296 subjects.