[2] Chadwick began his career in 1949 working as a medical student intern under Dr. Henry Kempe, an early leader in identifying and treating child abuse,[11] at the University of California-San Francisco.
[12] The following year, while at UCSF's Department of Pediatrics in the Medical School, Chadwick was awarded a five-year, $35,000 scholarship from the Sister Elizabeth Kenny Foundation for a research program seeking the causes of post-infection encephalitis.
[13] He then joined Children's Hospital Los Angeles in 1958 as a faculty pediatrician after Helen Boardman, a social worker who once served on the founding board of Parents Anonymous recruited him to look at child abuse.
[8] Chadwick spoke before the U.S. Congress in September 1985 about the Child Health Incentive Reform Plan, on behalf of the Western Association of Children's Hospitals.
[14] He was a researcher on shaken baby syndrome in the 1990s and a member of the American Academy of Pediatrics's child abuse and neglect committee.
[20] The American Professional Society on the Abuse of Children, in its online tribute, called Chadwick a "life-long rebel and innovator who made the world a better place through his thinking, sharing, and action.
"[11] The Chadwick Center was the beneficiary, for the first time, of the 114th Anniversary Charity Ball at the Hotel del Coronado in February 2023, with a $1 million donation made in advance by the Manchester Family Foundation.
"[18] In 2010, the American Medical Association presented him the Scientific Achievement Award for his pioneering work in child abuse treatment and prevention.