Traditional models of student success in higher education focus on access and retention of students, and fall short in their ability to explain the nuanced dynamics of identity formation that occurs for underrepresented STEM students. Drawing on Multicontextual Theory, I examine how academic environments offer non-traditional ways of developing an integrated "science identity" in underrepresented STEM students and offer benefits to these students in terms of attraction to STEM, socialization and persistence. The intersectional, mixed-method data for this dissertation include in-depth interviews, focus groups, and student survey responses from various STEM contexts across multiple institutions in the Southwest. I discuss how traditional academic cultural environments are experienced differently than alternative cultural (program) environments and the implications for integrated identity development. I argue that sociological theories of education such as Tinto and Weidman's of access and retention need to be revised to include the role of cultural context. Specifically, Multicontext theory, which encompasses the role of cultural context, pedagogy and student identity, elucidates the importance of providing Multicontextual environments for advancing inclusive excellence in higher education. [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.]