Robert Sinsheimer was born in Washington, the first scientist in is family. He was professor of biophysics at Caltech from 1957 to 1977, and was Chairman of the Division of Biology from 1968 to 1977. During this period he conducted a series of investigations into the physical and genetic characteristics of a bacteriophage called Phi X 174. These breakthrough studies illuminated the viral genetic processes. Sinsheimer and his colleagues also succeeded for the first time in isolating, purifying and synthetically replicating viral DNA.

In 1977, Sinsheimer left Caltech to become a chancellor of the University of California, Santa Cruz. One reason the position of chancellor appealed to him was that it provided a forum to address his concerns that had developed concerning the social implications and potential hazards of recombinant DNA technology and cloning methods. Sinsheimer was one of the first scientists to question the potential of molecular biology and the ethical implications of the developing technologies. He had become committed to promoting scientific literacy among non-scientists.

His early years at Santa Cruz were challenging. During his tenure the university re-established itself as a seat of research and academic excellence. Some of Sinsheimer's accomplishments included the establishment of the Kleck telescope, the establishment of programs in agroecology, applied economics, seismological studies, and a major in computer engineering.

Sinsheimer also participated fundamentally in the genesis of the Human Genome Project. In May of 1985, Sinsheimer organized a conference at Santa Cruz to consider the benefits of sequencing the human genome. From these and other such deliberations arose the Human Genome Project.