From 1974 to 1976 he was an assistant professor at Baylor College of Medicine in Houston, Texas, where he performed his postdoctoral research.

Rao was an honorary professor at Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore and was actively running its Chromatin Biology[4] laboratory until his death.

On several occasions, he served as a visiting professor at Baylor College of Medicine (1983, 1986), Harvard Medical School (1988–1990, 1993), Ludwig Institute for Cancer Research, and University of California at San Diego (1998).

In 2003, he was appointed chair and president of Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore.

He was a former chairman of the Board of Governors of Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala.

He was the chairperson for the Task Force on Human Genetics & Genome Analysis at the Department of Biotechnology, India.

As of August 2023[update], his 1993 publication[12] on colon cancer, published in Cell (journal), has been cited over 3700 times.