Sophomore collegiate student persistence is an often-overlooked problem for universities and a relatively nascent area of educational research. In order to address this issue and contribute to the body of research on this topic, the present study was conducted to determine the impact of supplemental advisory services on sophomore student persistence at a private, four-year university in the southeastern United States. The researchers were also interested in identifying student perceptions of the program's impact on their university experiences. To accomplish the study purpose, the researchers employed a mixed-methods research design including a causal-comparative research component, correlational research component, and qualitative case study component within a theoretical framework anchored by Tinto (1993) and Astin (1975, 1984/1999). Archival participants (n = 7,002) included all sophomore students (defined as students having earned between 30 and 63 credit hours and enrolled in the third or fourth semester of college) having accessed supplemental advisory services since the program's inception in 2015. Questionnaire participants (n = 21) included current sophomore students having utilized the program's services either directly or indirectly and interview participants (n = 10) included current sophomore students having utilized the program's services directly or indirectly. Questionnaire and interview samples were determined using a combination of purposive convenience sampling, self-identification, and snowball sampling. The researchers found the supplemental advisory programming office's impact on students to be moderate across several subgroups and that student perceptions of the office were more positive if those students had been subject to adverse life experiences during their collegiate journey, though many believed the office could do a better job of communicating its outreach and purpose to the student body. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]