Using cross-sectional analyses in conjunction with dynamic modeling (hierarchical linear modeling), the authors profiled 119 treatment foster care youth and constructed behavioral change trajectories for a subset of 97 children. Children generally showed improvements in internalizing and critical pathology problem domains but remained the same on measures of externalizing behaviors and total problem score. The number of previous out-of-home placements was positively associated with increased levels of psychiatric symptomatology and served as the most robust predictor for modeling treatment response trajectories across problem domains. Placement instability places the well-being of children at heightened risk, therefore, accurate assessment of child need and risk in relation to caregiver capacities is critical.