Female homeless youths are vulnerable to risky sex and substance use behaviors, yet they have strengths known as psychological capital. A quasi-experimental pre-post research design with repeated measures was used to examine the feasibility and preliminary efficacy of a brief intervention to enhance psychological capital, reduce health-risk behaviors, and achieve short-term behavioral goals. Study participants were 80 ethnically diverse homeless women between the ages of 18 and 23 years. Intervention participants had significant improvements in psychological capital, hope, resilience, and self-efficacy to refuse alcohol, social connectedness, and substance use (p < .05). There was a significant group by time interaction for safe sex self-efficacy; intervention participants had greater self-confidence in negotiating safer sex practices than comparison participants. At the follow-up post-test, 82% of intervention participants who remained in the study had met or exceeded their short-term goals. This brief, street-based intervention was feasible and showed preliminary efficacy.