Objectives: We conducted joint analyses from five randomized clinical trials (RCTs) of online family problem-solving therapy (OFPST) for children with traumatic brain injury (TBI) to identify child and parent outcomes most sensitive to OFPST and trajectories of recovery over time. Methods: We examined data from 359 children with complicated mild to severe TBI, aged 5–18, randomized to OFPST or a control condition. Using profile analyses, we examined group differences on parent-reported child (internalizing and externalizing behavior problems, executive function behaviors, social competence) and family outcomes (parental depression, psychological distress, family functioning, parent–child conflict). Results: We found a main effect for measure for both child and family outcomes [F(3, 731) = 7.35, p < .001; F(3, 532) = 4.79, p = .003, respectively], reflecting differing degrees of improvement across measures for both groups. Significant group-by-time interactions indicated that children and families in the OFPST group had fewer problems than controls at both 6 and 18 months post baseline [t(731) = −5.15, p < .001, and t(731) = −3.90, p = .002, respectively, for child outcomes; t(532) = −4.81, p < .001, and t(532) = −3.80, p < .001, respectively, for family outcomes]. Conclusions: The results suggest limited differences in the measures’ responsiveness to treatment while highlighting OFPST’s utility in improving both child behavior problems and parent/family functioning. Group differences were greatest at treatment completion and after extended time post treatment.