Before taking over the Knight Fellowships in 1998, Rensberger was a science writer or science editor for more than 32 years, beginning in 1966 at The Detroit Free Press. From there he went to The New York Times from 1971 through 1979. He left The Times to freelance and to become head writer of a PBS science series for children, "3-2-1- Contact!" In 1981, he became senior editor of Science 81 - Science 84 magazine. In 1984 Rensberger went to The Washington Post, where he served as science writer and science editor. He has written four books, most recently Life Itself: Exploring the Realm of the Living Cell. Rensberger has twice won the AAAS's top award for science writing. He also teaches science journalism in MIT's Graduate Program in Science Writing and is co-director of the Science Journalism Program at the Marine Biological Laboratory in Woods Hole.