Rosner was born in Berlin, Germany, where, at the age of three, he and his brother were on the last of the Kindertransport boats to the United Kingdom.
After the end of the Second World War, Rosner immigrated to the United States and was an undergraduate at Yeshiva University.
He qualified as an MD at the Albert Einstein College of Medicine, with the first graduating class in 1959.
He also published almost 800 articles and thirty-nine chapters in books on all aspects of Jewish medical ethics and Jewish medical history, and on many other topics, including haematology, leukemia, anaemia, immunology, and general medicine.
Rosner was an internationally known authority on medical ethics, having lectured widely on Jewish medical ethics throughout USA, and served as visiting professor or lecturer in Israel, England, France, Germany, Mexico, Canada, the Netherlands, South Africa, New Zealand and Australia.