Dr. Danielson became chair of the Johns Hopkins All Children's Department of Surgery in 2020 after serving in that role on an interim basis beginning in December 2018. He specializes in general surgery and was an early adopter of minimally invasive surgical techniques, developing expertise in treating chest wall deformities. He founded the first fellowship sponsored by Johns Hopkins All Children’s Hospital in pediatric surgery and was also instrumental in bringing the National Quality Improvement in Surgery Program to the institution. Dr. Danielson was named Johns Hopkins All Children’s Hospital physician of the year in the 2015 Johns Hopkins Medicine Clinical Excellence Awards and in 2017 was named director of innovative training and education. He is a retired U.S. Army officer.