We examined (1) the extent to which the family-centered program Intensive Family Treatment (IFT) succeeds in realizing beneficial parental psychological empowerment and child behavioral outcomes both in single-parent and two-parent families and (2) how these outcomes are influenced by the presence of a co-caregiver as a potential source of empowerment. A group of 140 single-mother and 156 mother–father families was compared. Information about empowerment of parents and children’s behavioral problems was collected at the start and end of IFT and analyzed with cross-lagged panel analyses. Although single mothers and mothers in two-parent families were comparable in the extent of improvements in psychological empowerment (effect sizes were respectively 0.52 and 0.57) and child behavioral problems (effect sizes were both 0.49), they differ in how these improvements were achieved. For single-parent families, more maternal empowerment at the start of IFT was directly related to positive changes in child behavioral problems (β = −0.246, p < 0.01). Among two-parent families, more paternal empowerment at the start was directly related to improved maternal empowerment (β = 0.249, p < 0.001) but maternal empowerment at the start was not directly related to changes in the father’s empowerment. This study stresses the importance of taking into account the presence or absence of a co-caregiver as a potential source of psychological empowerment during family-centered programs as IFT.