Purpose Medical schools increasingly incorporate ultrasound into preclinical curricula but face barriers including financial constraints, shortages of qualified instructors, and limited curricular space. This study explored how integrating ultrasound co-teaching into an existing first-year clinical skills course influenced preceptors’ teaching experiences and characterized areas for curricular improvement. Methods Ultrasound instructors rotated through classrooms during small-group physical examination skills sessions with 110 medical students, joining physical examination preceptors who taught remaining session content. Twelve ultrasound and traditional preceptors’ experiences were characterized through focus group interviews paired with inductive thematic analysis. Results Four themes were identified. First, the shared classroom fostered vicarious learning and novel instruction techniques but could feel disruptive to teaching. Second, ultrasound integration prompted physical examination preceptors to adopt a learner role. Third, students appeared to associate ultrasound with anatomy and physiology more than physical examination. Finally, ultrasound integration carries multiple logistical considerations. Conclusions Co-teaching ultrasound within clinical skills courses can promote learning and was associated with multiple effects on faculty preceptors and the teaching process. Those planning similar initiatives should consider strategies to optimize preceptor experiences, minimize disruptive potential, and promote connections between ultrasound and physical examination content.