Fredrickson has been a pediatric nurse throughout her career – as a staff nurse in the pediatric ICU and the pediatric emergency department; as a pediatric nurse practitioner at a school-based clinic, community health center, pediatric private office, for the county health department and as a community volunteer; and as a clinical nurse specialist in pediatrics/maternal-child health, the pediatric ICU, and the pediatric emergency department. She has been on the UCLA School of Nursing faculty since 1987, with major teaching responsibilities for pediatric nurse practitioner and pediatric clinical nurse specialist students. Fredrickson has taught in 20 courses and given guest lectures in seven others; these have included the physical assessment course as well as pediatric pre-licensure courses. She was one of six nurses chosen by the Emergency Nurses Association to develop the emergency nursing pediatric course. As a testament to her impact as a teacher, Fredrickson has seen many former students go on to serve as clinical preceptors and mentors of current students.