Tomori is president of the Nigerian Academy of Science. From 2004 until 2011 he was vice chancellor of Redeemer's University in Nigeria. From 1994 through 2004, as a virologist with the World Health Organization, he set up the African Regional Polio Laboratory Network, which provides diagnostic support for the global initiative to eradicate polio. He was head of the virology department at the University of Ibadan from 1984 until 1994, leading research on viral infections such as Ebola and Lassa fever. He holds a doctorate in virology from the University of Ibadan and a doctorate in veterinary medicine from Ahmadu Bello University, Zaria, both in Nigeria.