The increasing complexity of global challenges demands a STEM-enriched approach to learning for all students, regardless of their future career paths. Challenge-Based Learning (CBL) is a pedagogical method to foster a STEM-enriched education, engaging students in the design of societally impactful, interdisciplinary solutions. To investigate the potential of CBL, specifically in the context of Undergraduate STEM Education (USE), it is crucial to assess students’ affective development such as their attitudes, beliefs, and self-perceptions related to STEM. This dissertation explores the impact of CBL on student affect through three interconnected studies centered on a large-enrollment Bioinspired Design course. Chapter 1 explores overall growth in measures of science connection—Science Identity (SciID), Science Self-Efficacy (Eff), and Internalization of Scientific Community Values (Val)—using the Tripartite Integration Model of Social Influence (TIMSI) framework. Results demonstrated significant pre/post increases in SciID and Eff across five semesters, with Val remaining stable. Item level analyses revealed specific impacts of CBL activities on these affective measures, particularly in developing students’ confidence in creating novel technologies. Chapter 2 investigates the equity of these affective growth outcomes across seven demographic variables. Results indicated that the observed increases in science connection were largely equitable across diverse student populations, with differences in SciID development based on STEM major status and class status. Chapter 3 introduces and validates a novel affective construct: Innovation Skills self-efficacy. Developed using the Berkeley Evaluation & Assessment Research (BEAR) Assessment System, this construct provides a more targeted measure of self-efficacy aligned with the Innovation Skills needed for the future STEM-enriched workforce. Results showed approximately one standard deviation of pre/post growth, with a large effect size in the context of educational interventions. Collectively, this dissertation showcases the potential of CBL approaches in USE to foster equitable development of science connection and Innovation Skills self-efficacy across diverse student populations through comprehensive, psychometrically robust assessments of student affect. This research underscores the importance of holistic approaches to STEM education that cultivate not only knowledge and skills, but also the attitudes and beliefs necessary for success in the known and unknown STEM-enriched careers of the future.