Intern in pediatrics, then junior assistant resident Children's Hospital, Boston, 1968-1970. Staff associate National Heart Lung and Blood Institute, Bethesda, Maryland, 1970-1973. From instructor to associate professor pediatrics Harvard Medical School, Boston, 1973-1983.
Professor Rockefeller University, New York City, 1984-1986, Frederick Henry Leonhardt professor, since 1986, laboratory director, senior investigator. Director Laboratory of Bio-chemical Genetics and Metabolism, Rockefeller University, New York City, since 1984. Senior physician Rockefeller University Hospital, New York City, since 1984.
Member arteriosclerosis, hypertension and lipid metabolism advisory committee National Heart, Lung and Blood Institute, 1986-1990.
Served as surgeon United States Public Health Service, 1970-1973. Member American Association for the Advancement of Science, Institute Medicine (elected), National Academy of Sciences (elected), American Academy Pediatr. (E. Mead Johnson award 1984), American Heart Association (council on arteriosclerosis since 1974, credentials committee 1984-1986, award committees 1984-1987, chairman award committee 1987-1989, program committee 1986-1989, executive committee since 1988, New York City affiliate research council 1985-1987, chairman 1987-1989, chairman policy committee 1989-1991, chairman nominating committee 1992-1994, board directors 1987-1990, 92—, National Center vice president for research 1994, board directors 1994-1998, president-elect 1995, president 1996, past president 1997, Establishment Investigator award 1981-1986, Basic Research prize 1994 National Center Research Committee (vice chairman 1989-1990, chairman 1990-1992), Research program and Evaluation Committee (vice chairman 1992-1994, chairman since 1994), American Society Clinical Nutrition, Society Pediatrics Research, New York Academy of Sciences, American Federation Clinical Research, American Society Clinical Investigation (vice president 1987-1988), International Arteriosclerosis Society, American Society Biological Chemists, Association American Physicians, Institute of Medicine.