Goronwy O. Broun Sr. was born in Mobile, Alabama on July 31, 1895. He attended Spring Hill College from 1912 to 1914, graduating with a bachelor's degree in the latter year. As a scholarship student he earned his medical degree from Saint Louis University in 1918 and began his internship at Jewish Hospital, where he treated patients suffering under the Spanish influenza pandemic that erupted after the First World War. Broun himself fell victim to the disease and lost a sister to it. All these experiences provided the inspiration for his 50-year career in medical research.
In 1919 he joined Ralph A. Kinsella, Professor of Internal Medicine at the University, in his work on infectious diseases under a federal grant. Although the two men were unsuccessful in discovering either the cause of or the cure for influenza, they did establish that a decrease in blood platelets was responsible for the serious internal bleeding that accompanied severe cases of the disease. From 1920 to 1922 Broun was a fellow and assistant at the Rockefeller Institute for Medical Research in New York, and he served as an assistant in medicine at the Harvard Medical School at Boston City Hospital between 1922 and 1924. From 1924 until his death he was associated with the faculty of medicine at Saint Louis University.
Broun's delineation of the epidemiology and clinical features of St. Louis encephalitis during the 1930s was a major contribution to the knowledge of infectious diseases, and he also pinpointed the role of mosquitoes as the vectors for encephalitis. In the 1950s he did more work on influenza, making important strides in the understanding of the world-wide epidemiology of Asian influenza, or influenza A. His investigations were also instrumental in the isolation of the strain of Hong Kong influenza virus in 1972. Broun conducted further research on liver disease, anemia, nutrition, leukemia, and respiratory disease, especially emphysema. He became convinced that while smoking and air pollution were important factors in the development of emphysema, respiratory infections were also causative agents.
Broun was renowned as an educator of young physicians, and his advice was credited as a major influence in the rise to prominence of the School of Medicine. He was medical director of Firmin Desloge Hospital and of the University's outpatient department, director of the Department of Internal Medicine from 1954 to 1958, and Dean of the Medical School between 1962 and 1964. He continued at the University into his last years as Professor of Internal Medicine and Chairman Emeritus of the department as well as Dean Emeritus of the School of Medicine. In his long career he authored more than 100 scientific papers yet described himself as "a jack of many research trades but surely a master of none," explaining that he had produced many abstracts and short articles but few lengthy publications.
Broun received the Saint Louis University Alumni Merit Award in 1960 and was named a Knight of the Holy Sepulchre by Pope John XXIII the following year. In the late 1970s he was given the National Foundation of the March of Dimes Tribute Award for outstanding contributions to clinical medicine.
Broun died at his Central West End home at the age of 81 in 1977, less than a month after participating in the University's first annual Goronwy O. Broun Symposium on Influenza, an event that attracted leading scientists, virologists, and public health practitioners from around the nation. Broun was survived by his wife Emily, son Goronwy O. Broun Jr., Associate Professor of Internal Medicine at the University, two daughters, and 15 grandchildren.