Based on Astin's (1993) theory of involvement and Astin's (1991) college impact model a model of college student leader development was developed to examine the process of leader development among students who participated in sport during college. In addition, the differences between students who participated in different levels of sport with respect to leadership self-efficacy (LSE) and socially responsible leadership (SRL) values (HERI, 1996) were explored. Other factors such as involvement, positional leadership, and participation in mentoring were evaluated as college environment variables. This "ex post facto" study was a secondary analysis of data collected through the 2009 administration of the Multi-Institutional Study of Leadership (MSL). The MSL provided a national sample of senior undergraduate students. From this random samples of students who participated in intercollegiate (n = 349), club (n = 312), intramural ( n = 348), and recreational sports (n = 347), non-athletes (n = 349), and students who participated in multiple levels of sport (n = 347) were created for analysis. Two other samples were created to compare students who participated in any level of athletics (n = 995) to those that did not ( n = 999). Single and multi-group structural equation modeling (SEM) were used to interpret the results and determine the fit of the model. The results indicate college students who participated in any level of athletics scored higher than other college students in LSE at a statistically significant level after controlling for background, pre-college variables, and involvement during college. Differences also were also found between the levels of athletic participation with respect to leadership outcomes, with multiple-level and recreational sport participants scoring higher than club sport and non-athletes in positional leadership, LSE, and SRL. A small but significant difference was found in SRL based on gender, with women scoring slightly higher than men. No statistically significant differences in leadership outcomes were found based on race or National Collegiate Athletic Association (NCAA) division. The model of college student leadership development proposed in this study had acceptable fit across groups and explained 36% of the variance in LSE and 32% in SRL for the overall sample. The results indicated that mentoring, positional leadership, and pre-college LSE had direct effect on the development of LSE. While mentoring, involvement, and pre-college SRL predicted SRL. Mentoring was the strongest during college variable to predict both LSE and SRL across samples, indicating the importance of mentoring to college student-athlete leader development. Several differences between paths emerged between the groups. The study provided support for LSE and SRL as outcomes for students who participated in athletics during college, and the use of socially responsible leadership as a means to understand leadership development for college student who participate in athletics. The discussion includes practical applications of the results for universities, college sport programs, and students as well as recommendations for future research. [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/en-US/products/dissertations/individuals.shtml.]