Incidents of depression, anxiety, and suicidal ideation among adolescents have increased in recent years. Mental health interventions tailored to adolescents and families need to consider mechanisms for increasing enrollment and sustaining program engagement. A telephone-based, health coach intervention for adolescents and families was implemented at a Southeastern US health system with the goals of improving psychiatric appointment attendance, medication adherence, reduction in emergency department visits, and assisting with crisis management ("Youth and Family Engagement" [YFE] program). This study aims to explore patients' and parents' perceptions of a mental health program and the factors that impact enrollment and sustained engagement. Semistructured interviews were conducted with adolescent patients (n=9, 56%), parents (n=11, 92%), and clinicians who placed patient referrals (n=6, 100%). Interviews were in English (participants: 19/26, 73%) or Spanish (parents: 7/11, 64%), depending upon participants' preference. Interviews explored perceptions of the YFE program, experiences working with health coaches, suggestions for program changes, and program goals. The data were analyzed using inductive coding methodologies, with thematic analysis used to organize emergent themes. Two qualitatively trained researchers, one bilingual in English and Spanish, facilitated all data collection and collaboratively performed data analysis. The YFE program's structure was often mentioned as promoting engagement, with telephone appointments and health coaches' ability to accommodate inflexible work or school schedules alleviating participation barriers. Skills learned from health coaches were frequently referenced, with adolescents generally citing internal processes, such as positive thinking and mindfulness. Parents discussed behaviors relative to their children, such as improvements with discipline, setting boundaries, and improved parent-child communication. Many participants discussed the importance of health coaches assisting families in navigating social systems, such as accessing resources (eg, housing) and navigating school processes (eg, individualized educational plans), with clinicians suggesting an increased emphasis on adolescents' nutrition and engagement in primary care. Spanish-speaking parents highlighted numerous advantages of working with bilingual health coaches, emphasizing both enhanced communication and cultural understanding. They specifically noted the coaches' ability to grasp their lived experiences and challenges as immigrants in the United States, which significantly enriched their participation in the program. Prioritizing convenient engagement for adolescents and families may be important for sustained program participation, as inflexible schedules and competing priorities pose barriers to traditional appointments. Future programs should carefully consider health coach-participant relationships, specifically cultural competency, providing services in native languages, and assisting families with wraparound care, as these may be crucial to sustained engagement.