The purpose of this qualitative single case study was to explore how online undergraduate students experience, understand, and engage in successful course completion at an online for-profit university in the United States. The Community of Inquiry (CoI) model that focuses on meaningful learning experiences provided the study's conceptual framework. Three research questions guided this study and collectively included how online undergraduate students "experience", "understand", "and engage in" successful course completion? A qualitative methodology and single case study research design addressed the research questions. The researcher collected data from a sample of online undergraduate students at an online for-profit university in the United States. Purposeful sampling helped narrow the total sample to 56 participants from a private Facebook group that met the selection criteria. Data sources included two qualitative data sources of 10 semi-structured interviews and one focus group, and one quantitative data source of 56 closed-ended survey responses. Data analysis included Braun and Clarke's inductive thematic analysis and descriptive statistics. Nine themes emerged from 114 initial codes: support and recognition, faculty presence, functional online learning environment, school/life balance, personal responsibility and accountability, motivational mindset, self-awareness and preparation, intentional engagement and advocacy, and relationship building. The study conclusions found online undergraduate successful course completion can be obtained through intentional engagement, advocacy, support, connection, and a motivational mindset but is worthy of additional future exploration. [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.]