Research on first-generation college students' (FGCS) is centered around cultural, demographic, and personal characteristics and structural barriers that adversely impact their persistence and graduation from postsecondary institutions. Literature is limited in its examination of how FGCS' utilize their personal strengths and assets, institutional supports, and federal TRIO programs in achieving postsecondary success. Using transformative paradigm and intersectional identities research as analytic tools, the study explored how FGCS achieved postsecondary success. Findings from an explanatory, sequential mixed methods case study of University of Maryland College Park's SSS program 2014 cohort revealed that the main effect of being a FGCS on the number of credits earned towards graduating from the university in 6 years was not significant; however, the main effect of a student's racial background on the number of credits earned towards graduating within 6 years was significant. Survey findings showed that participants valued familial and peer support in their success and their personal strengths of being ambitious, ability to navigate challenging situations/people, took advantage of opportunities, and advanced planning to realize their goals. Participants also indicated UMCP activities that contributed to their success: field-based experiences, leadership roles, and culminating senior experience; however, most did not take advantage of undergraduate research or study abroad opportunities or felt UMCP helped them managed their non-academic responsibilities. Participants expressed the Summer Transitional Program and the interactions with their peers and the AAP-SSS program staff was instrumental in their success, along with other AAP-SSS programs and services. Participants were cognizant of their first-generation identity as a source of motivation and desire to support their families, but often linked it with another marginalized identity they embodied when sharing their experiences. Overall definitions of postsecondary success were categorized in several themes: being a part of STP/AAP; asking for help; having a support system; networking and internships; personal/financial well-being; and discovering passions/dreams. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]