This dissertation explores the intricate dynamics between the self-perceptions of undergraduate mathematics (UM) educators and their conceptions of excellent teaching practices conducive to student learning. Employing a sequential mixed methods approach, the study addresses two primary research questions. First, it investigates educators' self-perceptions within the realm of UM teaching, examining potential variances based on educators' Professional Status and Educational Institution (PSEI) affiliations and experience levels. Second, it delves into educators' perspectives on aspects of excellent UM teaching, scrutinizing potential disparities rooted in PSEI affiliations and experience levels, while also exploring the manifestations of Mathematics Teachers' Specialized Knowledge (MTSK) and teaching self-concept within these descriptors. Drawing upon Shavelson's self-concept (1976) framework and Carrillo and colleagues' (2018) MTSK framework, data collection involved a Likert-style questionnaire augmented by open-ended inquiries, followed by qualitative case studies featuring eight participants from diverse Carnegie classifications. Findings demonstrate educators' overall confidence in their teaching abilities, with notable discrepancies observed among educators from associate's colleges and doctoral universities. Through thematic analysis, key dimensions of excellent teaching emerged, including active learning, student engagement, problem-solving, and positive learning environments. This study yields implications for educational practice and institutional policy. Educators can leverage identified themes to inform professional development initiatives tailored to enhance UM teaching effectiveness. Furthermore, the validated instrument offers institutions a means to assess educators' confidence levels, facilitating targeted support within mathematics department. In conclusion, this dissertation contributes valuable insights into the multifaceted interplay between educators' self-perceptions, teaching practices, and student learning outcomes within the context of UM instruction. [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.]