Women and students of minority race/ethnicity continue to be underrepresented in many science and engineering fields. Access to special programs, mentors, and internships may influence awareness, intention, and persistence in science and engineering. This dissertation investigates the experiences, beliefs, and career intentions of undergraduate students from historically underrepresented groups as they engage in a federally funded grant program, "Sustainable Futures", a combination of distance courses, workshops, and a summer internship, intended to increase awareness, interest, and diverse participation in bioeconomy-related industries. Drawing on quantitative and qualitative methods, the three studies presented in this dissertation are: 1. developing and validating two new survey instruments for measuring beliefs and career interest in bioproducts and bioenergy and examining demographic differences for a large group of undergraduate students, 2. reporting changes in beliefs and career intentions as students participate in Sustainable Futures Program activities over a two-year period, and 3. examining career narratives and personal and contextual barriers and supports to career development for students transferring from two-year to four-year institutions. This work informs efforts to increase representation and access to science and engineering careers. The first study describes the development, validation of two survey instruments recommended for measuring the impacts of coursework, research, and internships. The Beliefs about Bioproducts/Bioenergy (BABB) and Career Interest in Bioproducts/Bioenergy (CIBB) surveys were developed and validated with undergraduate students enrolled in courses in a natural resources college at a research university in the southeastern United States. Surveys conducted independently for the BABB (N = 168) and CIBB (N = 203) were analyzed using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) and demonstrated validity and reliability with the undergraduate student population. Students with majors closely related to bioproducts/bioenergy held significantly more positive personal and societal beliefs about bioproducts/bioenergy, as well as higher interest in bioproduct/bioenergy related career interests. Differences were also observed based on gender, major, and class standing, but not by race/ethnicity groups. Measuring student beliefs about bioproducts/bioenergy and interest in related careers allows for gauging trends and changes that may influence public behavior toward environmental choices along with preparing a diverse workforce to support a sustainable bioeconomy. The second study used a convergent mixed method approach to examine changes in undergraduate career intention and beliefs about bioproducts/bioenergy during their participation in the Sustainable Futures Program. The CIBB and BABB surveys were administered at various time points (N = 12) throughout the program and paired with student reflections about their career intentions and beliefs about bioproducts/bioenergy (N = 14). Of the students who completed the program, 58% intended to pursue bioproduct/bioenergy careers and all students had refined their career goals over time. With the influence of program courses and internships, students developed technical knowledge and skills, explored career options, and were inspired or recommitted to specific career goals. Students also maintained highly positive beliefs throughout their program experience regarding the value of bioproducts/bioenergy. They considered themselves consumers of bio-based goods, advocates for a sustainable bioeconomy, and future employees in related industries. The third study, a longitudinal narrative case study, detailed the experiences of six community college transfer students who participated in the Sustainable Future Program. Biographical mapping, student interviews, and reflective writings over two years were analyzed, drawing from social cognitive career theory. Students described institutional, social, and internship-host provided supports. The barriers they identified were more diverse, and often were overcome by institutional and financial supports. All participating students attributed their sense of job readiness to their internship participation. Understanding and providing these supports and addressing barriers in career development experiences will help educators, advisors, and academic programs to better serve transfer students. [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.]