Hornig was born in
Milwaukee, Wisconsin, the son of Chester Arthur Hornig and Emma Knuth. He attended
Milwaukee Country Day School, then earned his undergraduate degree in chemistry from
Harvard University. He was awarded his Ph.D. from
Harvard University in 1943, at the age of 23, with a dissertation on
An Investigation of the Shock Wave Produced by an Explosion in Air. On July 17, 1943, he was married to scientist
Lilli Hornig. The couple had four children together: three girls, Joanna, Ellen, and Leslie, and one boy, Christopher. After graduating, he started work at the Underwater Explosives Laboratory of the
Woods Hole Oceanographic Institute. While there, according to one obituary, he received an invitation to begin a new job, but he was not told what his duties would be, nor, initially, to where he would relocate. At first he refused, but Harvard University President
James B. Conant helped persuade him to reconsider. He helped prepare the first atomic bomb,
Trinity, and witnessed its explosion, the first detonation of a nuclear device. He was sent up to the top of the tower twice the previous day to reassure a nervous
Robert Oppenheimer that all was well and after working on the high voltage capacitors that fire the multiple detonators, he was the last man to leave the tower. In 1946 he joined the staff of
Brown University as an assistant professor, and became a full professor in 1951. From 1951 to 1952 he was associate dean of the graduate school, then acting dean the following year. In 1957 he became a member of the
National Academy of Sciences and the same year he moved to
Princeton University in 1957. Later became chairman of the Princeton chemistry department. Shortly before President
John F. Kennedy was assassinated in 1963, he announced Hornig as the presidential science advisor. Hornig assumed office on January 24, 1964, but did not get along with the new president,
Lyndon Baines Johnson, who had poor relationships with many scientists. In 1970 he became president of
Brown University, and he remained in office until he resigned in 1976. The end of his term was noted for financial cutbacks at the university, which was met by student protests. Thereafter he became Professor of Chemistry in Public Health at Harvard University. From 1987 to 1990 he served the Harvard University School of Public Health as chairman of the Department of Environmental Health. He retired in 1990. Since 2013, Hornig has been listed on the Advisory Council of the
National Center for Science Education. Hornig died from
Alzheimer's disease in
Providence, Rhode Island, on January 21, 2013. ==In popular culture==