The current study is the first repeated-measures design exploring the impact of child-centered play therapy (CCPT), an evidence-based child psychotherapy intervention, on autistic children's social-emotional assets, and emotional and behavioral problems across four times during intervention based on teacher reports. Participants consisted of 19 autistic children recruited from two Title-1 elementary schools in the southwest United States who were aged between 5 years and 8.25 years (M = 6.22, SD = 0.91), presented with varied levels of cognitive functioning and speech and language abilities. Over 60% of participants were identified by their parents as children of color. Results indicated participants' increased time in CCPT predicted statistically significant improvement in social-emotional assets measured by Social-Emotional Assets and Resilience Scales-Teacher (SEARS-T) total score with a large effect size. Results also indicated participants' increased time in CCPT predicted a statistically significant reduction in emotional and behavioral problems of irritability, social withdrawal, and hyperactivity/noncompliance, measured by Aberrant Behavior Checklist-Second Edition (ABC-2), with large effect sizes. Findings of this study revealed substantive changes in social-emotional assets as early as 8 CCPT sessions, and reduction of emotional and behavioral concerns as early as 12 CCPT sessions. Clinical significance, implications for practice, and limitations of the study are discussed.