The purpose of this study was to investigate the relationship between exposure to traumatic events and adaptation outcome among first-year college students, and to examine the effects of psychosocial resources on first-year college students with a history of exposure to traumatic events. Survey data from 2,806 first-year college students of six universities in Taiwan were analyzed using structural equation modeling. The study found approximately 41% of respondents reported at least one traumatic event and the group of students who reported having experienced any trauma in the past scored lower on adaptation index than participants who did not. Results also indicated that well-adjusted students who had experienced any trauma had greater optimism, higher self-esteem, stronger secure attachment, more perceived social support, and greater use of proactive coping, as compared to maladaptive students. These psychosocial resources and the number of different types of traumas explained about 55% of the variance in adaptation index. The effect of self-esteem on adaptation index was the most significant. Moreover, the path model indicated that perceived social support and proactive coping partially mediated the relationship between optimism/self-esteem/attachment and adaptation index. In addition, the study found that the number of different types of traumas was a predictor of perceived social support and proactive coping. Implications for these complex relations are discussed for both counseling interventions and future research.